Habit

All but one species are large, woody vines; Mezia includens has been reported to reach 40 m. The exception is Mezia huberi, a shrub or small tree to 8 m tall. The young shoots and inflorescence axes are flattened or quadrangular. In most species, the vegetative branches become terete or nearly so with age. In Mezia rufa, the quadrangular aspect is retained for a longer period, and branches bearing mature leaves often are narrowly 4-winged.

Leaves and stipules

As is typical for the family, the leaves are opposite. The laminas are elliptical to ovate or obovate, and also sometimes lanceolate (e.g. Mezia peruviana). The apex in most species is acuminate, with the acumen to 2 cm long. It is apiculate in Mezia bahiana and varies in M. araujoi from apiculate to acuminate to rounded and even retuse. The base of the lamina varies from attenuate to cuneate to truncate or rounded. The margin may be thickened or slightly so, and flat to recurved.

The lamina is adaxially sericeous only at the earliest stages and soon becomes glabrous. Most species show the same pattern abaxially, although the hairs are more tardily lost. The abaxial surface may appear glabrous to the naked eye although minutely sericeous or scattered with isolated hairs; the epidermis is always evident. Of the four exceptions, Mezia huberi, M. rufa and M. sericea have the laminas abaxially persistently and densely sericeous; the epidermis is obscured. The hairs are straight, up to 0.4 mm long, and brown; however, the colour may fade with age, and the hairs become translucent. This is seen in Mezia rufa, for which collections with young as well as very large, old leaves are available. Mezia tomentosa is unique in the genus in its abaxially densely velutinous or tomentose vesture; the dark or reddish brown hairs are V-, Y- or T-shaped and persistent.

As a rule, each lamina bears a large gland at the base on either side of the costa, sunk in crypts in fully mature leaves but may be flat in earlier stages. Yet, the presence of such glands is variable, and they may be absent. In Mezia bahiana, the large glands are borne at the apex of the petiole, and in M. araujoi these glands are sometimes placed halfway on the petiole. In Mezia rufa and M. sericea, the basal glands may number four or occasionally up to six. Mezia tomentosa has eglandular leaves; however, this species is known from only two collections.

In addition to the basal glands, the abaxial surface of the lamina may also bear one to many smaller impressed glands in a line within each margin, often towards the apex. The presence or absence of these smaller glands is also variable within each species and even individuals. Only Mezia bahiana, known only from the type, and M. tomentosa lack such surface glands.

The stipules are minute triangular rudiments to 0.2 mm long, borne on an interpetiolar ridge and often hidden by stem hairs. They are caducous and therefore rarely seen, but they leave interpetiolar scars to 0.5 mm wide.

Inflorescence

The large, multibranched, axillary and terminal inflorescences are covered by a dense vesture of appressed brown hairs and contain many greatly reduced bract-like leaves. The lateral branches may be subtended by one or rarely even two smaller subsidiary axes (e.g. Fig. 7D), these sometimes terminating in only one umbel. The bilaterally symmetrical flowers are ultimately grouped in 4-flowered umbels, which are borne on a short stalk with usually one pair of deciduous sterile bracts placed from near the base to near the apex. Each well-developed peduncle is subtended by a floriferous bract and terminates in a pair of large cymbiform bracteoles that in turn subtend a rudimentary pedicel. In other genera of Malpighiaceae old flowers break off at the joint between peduncle and pedicel, but in Mezia they abscise at the base of the peduncle.

The large bracteoles cover the flower in bud, the inner enclosing the flower bud and the outer partially enclosing the inner bracteole, resulting in a distinctive globose or subglobose ‘bud’. The bracteoles spread during anthesis, but once the petals are shed they again enclose the flower, but now loosely (Fig. 2B,C). They spread again or reflex with the maturation of the fruit. In Mezia bahiana, M. beckii and M. mariposa, the outer bracteole is marked with a prominent gland (Fig. 2D). The floriferous bracts abscise during anthesis, but the bracteoles are usually persistent past the fruiting stage. In most species the floriferous bracts are much smaller than the bracteoles, but they are subequal in Mezia fanshawei and nearly as large in M. russellii. Both bracts and bracteoles may be adaxially sericeous or sparsely so or only distally or near the margin or glabrous. This adaxial vesture may thin or be lost with age, such that bracteoles remaining on fruiting stalks may superficially appear to be glabrous.

Fig. 2.

Floral aspects of Mezia. A and B, M. angelica. A, Flower. B, Flower bud opening, the bracteoles and sepals spreading (left); flower post anthesis, the bracteoles and sepals becoming erect again (right). C and D, M. mariposa. C, Two open flowers, two buds with the bracteoles beginning to open and revealing enfolded petals (buds in centre), young buds with the bracteoles still closed (buds at left). D, Closed buds borne on peduncles, each peduncle subtended by a bract; each arrow points to a gland on the outer bracteole. Photographs: A and B, Carol Gracie; C and D, Marcelo Pace.

Calyx

The calyx is composed of five narrow sepals with an obtuse apex and often revolute margins. Like the bracteoles, the free part of the sepals spread as the petals expand and return to more erect posture once the petals fall. All sepals are glabrous adaxially, and in all species but one densely brown-tomentose abaxially. The exception is Mezia russellii, in which the sepals have usually plane margins and are abaxially hirsute with straight spreading whitish to stramineous hairs. This species also differs in that the sepals exceed the glands by only 1–2 mm; in other species, the sepals project (3–)4–6(–7.5) mm beyond the glands. The anterior sepal is eglandular, and the lateral four bear a pair of large compressed glands at the base, which may be distinct or partly to completely connate. Rarely, glands are also present on the anterior sepal in aberrant individuals. The calyx is persistent past the fruiting stage.

Corolla

The five petals are yellow, and the posterior petal commonly is marked with red in the centre. In dried specimens, such a red spot may be indicated by a darkened area on the limb. The limb of lateral petals varies from orbicular to obovate and of the posterior petal to elliptical as well; it often has a crumpled appearance. In general, the anterior-lateral petals range from 10 to 16 mm in diameter and are somewhat larger than the posterior-lateral ones; the posterior petal, the ‘flag’, is the smallest, ranging from 5 to 9 mm. In Mezia fanshawei, the lateral petals are subequal and measure 7–8.5 mm in diameter. Only Mezia mariposa has all petals glabrous. In other species the lateral petals are abaxially sericeous, with a patch of white hairs mostly in the centre and sometimes extending to the claw; in Mezia includens such hairs are light brown. The posterior petal is abaxially pubescent as well in Mezia angelica, M. araujoi, M. bahiana and M. beckii. The petals of Mezia curranii and M. tomentosa are unknown.

Androecium

The 10 stamens are heteromorphic and usually persistent through the fruiting stage (the stamens of Mezia tomentosa are unknown). In most species, the stamen opposite the posterior petal is the smallest and that opposite the anterior sepal the largest. The filaments are connate in the basal 1/2 to 2/3 but often in the basal 3/4 in those opposing the posterior petal and posterior-lateral sepals. The anthers are glabrous in Mezia sericea, M. huberi, M. includens and M. rufa; the anthers of M. peruviana usually have a few hairs scattered along the locules. In the remaining species the anthers are tomentose, usually more abundantly in those opposite the sepals, with the vesture concentrated along the locules and/or the apex and/or the base (and then perhaps extending unto the filaments). The anthers of Mezia mariposa are glabrous in stamens opposite the petals but bear hairs in those opposite the sepals. The connective is enlarged and projects beyond the locules (up to 1.5 mm in Mezia includens) in anthers opposing the sepals in all species but M. angelica, M. araujoi, M. bahiana, M. beckii and M. mariposa. In anthers opposing the petals, the connective mostly equals the locules or exceeds them only slightly, although in the variable Mezia includens the connective sometimes extends to 0.4 mm beyond the locules. Two exceptions are Mezia peruviana, with all anthers having the connective exceeding the locules, and M. sericea, with only those opposing the posterior-lateral petals having the connective extended.

Gynoecium

The tricarpellate ovary terminates in three free styles, which have the stigma located at the internal angle at the apex (“internal stigma” in some literature on the Malpighiaceae). The styles of all but five species are straight and erect. In Mezia angelica, M. araujoi, M. bahiana, M. beckii and M. mariposa, the posterior styles are lyrate, and the anterior style is often inclined towards the posterior petal. In these the style apex is dorsally acute or truncate, or sometimes drawn out into a small spur; it is rounded or blunt in Mezia russellii and M. tomentosa.

Fruit

The fruit of Mezia is a schizocarp, which breaks into three round to oblate samaras borne on a pyramidal torus. The largest samaras measure more than 10 cm in diameter (Mezia includens) and the smallest 3 cm (M. huberi). Each samara has two large lateral wings that are confluent, forming a single wing incised only to the apex of the nut, as well as a much shorter dorsal wing. Mezia angelica and M. huberi have one additional winglet or crest between the dorsal and lateral wings, and in the other species that area is filled with a network of intermediate winglets and/or crests. In Mezia curranii and M. russellii, this network is separated from the dorsal wing by an intermediate winglet, and in M. tomentosa the dorsal wing is so short that it is indistinguishable among the ruffles of intermediate winglets. The butterfly-shaped samaras of Mezia mariposa are unique in the genus in that the lateral wings remain separate, and additional ornamentation between the dorsal and lateral wings is absent.

In most species, the adaxial face of the samara is unornamented or may bear shallow horizontal ribs radiating from the nut. In Mezia araujoi, the ribs are prominent and may extend into winglets. In Mezia angelica, each side of the nut has one flat crest or winglet separate and parallel to lateral wing. A more intricate pattern is shown in Mezia beckii, in which some of the ribs radiating from the nut form winglets adnate to the lateral wing and sometimes are also basally connate. In all species, the areole is bordered by two strong ribs, which usually remain on the samara at the time of abscission. Only immature samaras were seen for Mezia fanshawei, but they appear to follow the common pattern. Fruits are unknown for Mezia andersonii, M. bahiana and M. peruviana.

Etymology

Mezia andersonii commemorates William Russell Anderson (1942–2013), who devoted his career to the study of Malpighiaceae.

Mezia andersonii is known only from the type, collected in dry tropical forest of Amazonas, Peru (Fig. 1). It is distinctive among species with glabrous leaves and erect styles in its tomentose anthers, the connective not or barely exceeding the locules, and the adaxially sericeous bracts and bracteoles. The habitat is also noteworthy, because most species are found in moist to wet forest.

Fig. 4.

Mezia angelica. A, Leafy stem, with enlargement of abaxial surface to show persistent hairs. B, Portion of inflorescence. C, Umbel of four flower buds. D, Opening flower bud. E, Flower with petals removed, subtended by persistent bracteoles (above), and same with bracteoles half cut away (below), the eglandular anterior sepal in centre. F, Abaxial view of lateral sepal with two nearly connate glands. G, Flower (left) in face view with posterior petal at top; flower (right) in lateral view with two petals removed and posterior petal at right. H, Androecium, adaxial view, stamen fifth from right opposite posterior petal. I, Lateral (far left) and adaxial (near left) views of anthers opposite petals, and lateral (near right) and adaxial (far right) views of anthers opposite sepals. J, Gynoecium, anterior style in centre, and enlargement of style apex. K, Samaras, abaxial view (above) and adaxial view (below). L, Cross-section of samara, showing large lateral wing, smaller dorsal wing, single winglets on each side of dorsal wing, and single winglets outside lateral wings. Scale bar equivalents: A and B, 5 cm; C–E, 1 cm; F, 4 mm; G, 1 cm; H, 4 mm; I, 2 mm; J, 4 mm; K and L, 2 cm. Based on: A–J, Mori et al. 20945 (NY); K and L, Silva 2830 (NY). Drawn by Bobbi Angell.

Woody vine; stems sericeous when young, soon glabrescent, young axes flattened or quadrangular, eventually becoming terete. Lamina of larger leaves 12–20(–24) × 4.5–7.6(–9.8) cm, elliptical or somewhat ovate or obovate, apex abruptly short-acuminate with the acumen 5–10 mm long, base truncate or cuneate, margin not or only slightly thickened and flat, adaxially and abaxially sericeous when young but soon glabrescent to glabrous, older laminas abaxially appearing glabrous to the naked eye but sprinkled with minute widely spaced straight appressed hairs to 0.3 mm long, eventually glabrous, abaxially bearing a pair of large glands at base sunk in crypts or eglandular, occasionally with a row of small impressed glands within each margin distally, costa slightly impressed adaxially and prominent abaxially, 5–8 pairs of principal lateral veins and reticulum prominulous adaxially and prominent abaxially; petiole 15– 30 mm long, sericeous to glabrate; stipules caducous. Inflorescence terminal and axillary, multibranched, some lateral axes subtended by an additional floriferous axis; stalk of lateral umbels 6–16 mm long, bearing 1 pair of deciduous eglandular sterile bracts 2–2.5 mm long in proximal 1/4 to 1/3; floriferous bracts 4–6.5 mm long, broadly obovate, concave, apex broadly rounded, adaxially sparsely sericeous to glabrate, deciduous before or during anthesis; peduncle 7–14 mm long in flower and fruit, thickened in fruit; bracteoles 5–7(–8) mm long, adaxially glabrous to sparsely sericeous proximally, apex emarginate or bifid, midrib usually raised abaxially, eglandular, mostly persistent past maturity of the fruit; pedicel 0–0.8 mm long in flower, to 2 mm long in fruit. Sepals 4–6 mm long beyond glands, 2–3 mm wide, spatulate, strongly revolute along sides, abaxially densely brown-tomentose, the anterior eglandular, the lateral 4 biglandular, glands nearly or completely connate, 2–3 mm long, the pair 1.8–3 mm wide, obovate. Lateral petals yellow, abaxially white-tomentose in centre of limb, margin erose, base truncate, claw of anterior-lateral petals c.4 mm long, limb 11–13 mm in diameter, orbicular to broadly obovate, base truncate, claw of posterior-lateral petals c.3 mm long, limb 9–10 mm in diameter, orbicular; posterior petal yellow, red in the centre, abaxially white-sericeous, claw 3.5 mm long, constricted at apex, limb 6–8 mm in diameter, orbicular, base truncate or slightly cordate, margin proximally dentate or short-fimbriate and distally erose, eglandular. Filaments tomentose distally, connate in the proximal 1/4, 2–4.2 mm long, shortest opposite posterior and anterior-lateral petals, longest opposite anterior-sepals, those opposite posterior-lateral petals somewhat stouter than all others; anthers all tomentose at base, those opposite sepals 1.2– 1.8 mm long, the connective slightly exceeding the locules, anthers opposite petals 1– 1.7 mm long, the connective not exceeding the locules. Ovary c.1.5 mm long; styles nearly terete, apex dorsally truncate, proximally sericeous in proximal 1/4 to 1/2, anterior style 3–3.5 mm long, nearly straight and erect or inclined slightly towards posterior petal, posterior styles 3.5–4 mm long, lyrate or sigmoid. Samara 55–80 mm in diameter, oblate, wings thinly sericeous; nut 11–13 mm long, sericeous, adaxially with 1 flat winglet or crest 1–9(–15) mm wide on each side of nut, outside and parallel to lateral wing; lateral wing 25–34 mm wide, continuous at base, incised to nut at apex, margin entire or repand; central dorsal wing 18–33 × 7–14 mm, semicircular or irregularly repand, with 1 flat winglet 3–7 mm wide on each side of and parallel to dorsal wing; areole 9–13 × 2–4 mm, narrowly ovate or elliptical; torus 1–2 mm high.

Distribution and habitat

Brazil (eastern Amazonas, Pará), southern Guyana, French Guiana, Peru (Loreto), to be expected in Suriname; in moist forest; 50–360 m. Figure 1.

Mezia angelica differs from all other species with circular samaras, except M. huberi, in having one additional winglet on each side and parallel to the dorsal wing as well as adaxially parallel to the confluent lateral wings. It is one of five species in which the posterior styles are lyrate instead of erect. Of those five, only Mezia araujoi also has the outer bracteole eglandular but differs in floral aspects in addition to the samara structure. Mezia angelica has not been reported from Suriname but should be sought there.

The record from Peru is listed with uncertainty. The specimen has only two short, developing inflorescences. Dissections of flower buds showed the bracteoles to be glabrous and the posterior petal and the anthers to be pubescent, aspects that fit Mezia angelica; however, the styles are at too rudimentary a stage to suggest their mature form.

Fig. 5.

Mezia araujoi. A, Flowering branch. B, Large leaf, abaxial view. C, Large leaf, adaxial view. D, Glands at apex of petiole, adaxial view. E, Umbel of four flower buds. F, Flower subtended by bracteoles, posterior petal at top. G, Lateral petal (left), abaxial view, and posterior petal (right), abaxial view. H, Partial androecium, with claw and base of limb of posterior petal at right and basal portion of anterior sepal at left. I, Anther, lateral-abaxial view. J, Gynoecium, anterior style in centre. K, Samara, abaxial view. L, Samara, adaxial view. Scale bar equivalents: A–C, 4 cm; D, 4 mm; E, 2 cm; F and G, 8 mm; H, 2.7 mm; I, 2 mm; J, 4 mm; K and L, 4 cm. Based on: A–J, Heringer 16050 (MICH); K and L, Magalhães 17528 (IAN). Drawn by Karin Douthit.

Woody vine to 18 m; stems sericeous when young, mostly soon glabrescent, young axes flattened or quadrangular, eventually becoming terete. Lamina of larger leaves 11–26.5 × 5–15 cm, elliptical to broadly so to broadly oblong or somewhat ovate or obovate, apex mostly short-acuminate (acumen to 10 mm long) or apiculate or sometimes rounded or occasionally retuse, base truncate or cuneate, margin not or slightly thickened and flat, adaxially and abaxially sericeous when young but very soon glabrescent to glabrous, often some hairs retained on the costa and near base abaxially, the straight appressed hairs to 0.6 mm long, abaxially bearing a pair of large glands at base sunk in crypts or eglandular or the glands halfway at apex of petiole, commonly with a row of several small impressed glands within each margin mostly in the distal 1/2, costa slightly impressed or flush adaxially and prominent abaxially, 5–7 pairs of principal lateral veins and reticulum prominulous adaxially and prominent abaxially; petiole 14–30 mm long, sericeous to glabrate; stipules caducous. Inflorescence terminal and axillary, multibranched, some lateral axes subtended by an additional floriferous axis; stalk of the umbel 4–11 mm long, bearing 1 pair of deciduous eglandular sterile bracts 3.5–4.5 mm near base to slightly above the middle; floriferous bracts 6–7 × 4.5–6 mm, obovate, concave, apex broadly rounded or bifid, adaxially glabrous, deciduous before or during anthesis; peduncle 8.5–10.5 mm long in flower, not or slightly elongated in fruit and thickened; bracteoles 7–7.5 mm long, adaxially glabrous, apex emarginate or bifid, midrib not or slightly raised abaxially, eglandular, mostly persistent past maturity of fruit; pedicel 0.5–0.8 mm long in flower, to 2 mm long in fruit. Sepals 4.5–5.2 mm long beyond glands, 1.7–2.2 mm wide, spatulate, laterally revolute, abaxially densely brown-tomentose, the anterior eglandular, the lateral 4 biglandular, glands connate, 1.8–2.5 mm long, the pair 1.5–2 mm wide, obovate to square. Lateral petals yellow, abaxially white-sericeous-tomentose in centre of limb and on claw, limb elliptical to obovate, base acute, margin erose to irregularly dentate, claw 3–3.5 mm long, limb of anterior lateral-petals 11–12 × 7–8 mm, limb of posterior-lateral petals 9.5–10.5 × c.7 mm; posterior petal yellow, red in the centre, abaxially white-sericeous in centre of limb and on claw, claw 2.8–3 mm long, constricted at apex, limb 8–8.5 × 5–5.5 mm, elliptical to obovate, base acute, margin denticulate-fimbriate, gland-tipped in the proximal 1/4 to 1/3. Filaments connate in proximal 1/5 to 1/4, those opposite sepals glabrous, those opposite petals distally tomentose, 2–3.5 mm long, shortest opposite posterior petal, longest opposite anterior sepal, those opposite posterior-lateral petals much stouter than all others; anthers tomentose at base and with scattered hairs distally, those opposite sepals 1.3–1.5 mm long, the connective slightly (c.0.1 mm) or not exceeding the locules, those opposite the petals 1.4–1.7 mm long, the connective not exceeding the locules. Ovary 1.2–1.5 mm long; styles nearly terete, apex dorsally acute, the proximal 1/4 sericeous, 3–4 mm long, the posterior slightly longer than the anterior, anterior style nearly straight and erect or inclined slightly towards posterior petal, posterior styles lyrate or sigmoid. Samara suborbicular, (60–)70–80 mm in diameter, wings sparsely sericeous to glabrate; nut 12–13 mm long, sparsely sericeous, adaxially with a series of ribs radiating from areole, with some of these ribs expanded or not into winglets; lateral wing 25–35 mm wide, semicircular, continuous at base, incised to nut at apex, membranous, entire or repand at margin; central dorsal wing 25–35 × c.10 mm, semicircular or irregularly repand, with a network of interconnected shorter parallel and transverse winglets between the dorsal and lateral wings; areole 10–15 × 3–4 mm, narrowly elliptical; torus 2.5–3.5 mm high.

Distribution and habitat

Brazil (Espírito Santo, Minas Gerais, Rio de Janeiro); in moist forest; [sea level to] 550 m. Figure 1.

Mezia araujoi and M. bahiana are disjunct from the mainly Amazonian distribution of the genus. They both belong to the group of five species with lyrate instead of erect posterior styles. Of these, Mezia bahiana, M. beckii and M. mariposa are readily separated by the large gland borne on the outer bracteole. Mezia angelica, of the Guianas and eastern Amazonian Brazil, differs in its samara, lacking abundant winglets between the dorsal and lateral wings, and in aspects of the corolla.

Fig. 6.

Mezia bahiana C.E.Anderson. A, Leaf, adaxial view. B, Detail of basal glands on petiole. C, Umbel of flower buds (one removed). D, Flower bud enclosed in bracteoles; outer bracteole with large gland. E, Flower in face view, posterior petal at top. F, Posterior petal, showing abaxial vesture. G. Gynoecium, anterior style in centre. H, Anther and portion of filament. Scale bar equivalents: A, 1 cm; B, 4 mm; C, 1 cm; D, 5 mm; E, 4 mm; F, 2.4 mm; G, 2.5 mm; H, 1.3 mm. Based on Amorim et al. 3226 (MICH). Drawn by John Megahan.

Woody vine to 20 m; stems glabrous (only short portion with two nodes seen). Lamina of leaves 11.5–13.5 × 6–7.5 cm, elliptical, apex apiculate, the apiculum to 2 mm long, base attenuate, margin slightly thickened and flat, glabrous at maturity or abaxially with a few scattered brown hairs to 0.3 mm long near base, without impressed glands inside margin, costa impressed adaxially and prominent abaxially, 4 or 5 pairs of principal lateral veins and reticulum slightly prominulous adaxially and prominent abaxially; petiole 2.5–3 cm long, glabrous, bearing a pair of large glands sunk in crypts at apex; stipules caducous. Inflorescence multibranched, lateral axes often subtended by 1 or 2 additional floriferous axes; stalk of the lateral umbels 7–10 mm long, bearing 1 pair of caducous eglandular sterile bracts c.3 mm long in proximal 1/4 to 1/2; floriferous bracts 5–6.5 mm long, obovate, conduplicate, apex broadly rounded, adaxially glabrous, deciduous at onset of anthesis; peduncle 7–9.5 mm long in flower; bracteoles 7–7.5 mm long, adaxially glabrous, apex broadly rounded to emarginate or bifid, the midrib slightly raised abaxially, the outer bearing 1 protuberant circular gland 1.3–1.7 mm long abaxially at base, the inner eglandular, pedicel 0.5–1 mm long in flower. Sepals 4–6 mm long beyond glands, 2–2.5 mm wide, spatulate, laterally revolute, abaxially densely brown-tomentose, the anterior eglandular, the lateral 4 biglandular, the glands connate, 2.3–2.7 mm long, the pair 2–2.3 mm wide, obovate or quadrate. Lateral petals yellow, abaxially white-sericeous-tomentulose in centre of limb and on claw, base acute or briefly truncate, margin erose to irregularly denticulate, claw 3–3.2 mm long, limb of anterior-lateral petals 14–15 × c.11 mm, broadly obovate, limb of posterior lateral petals 11–12 × 10–11 mm, broadly ovate or broadly oblong; posterior petal yellow, red in centre, abaxially densely white-tomentulose, claw 3.6 mm long, thick, constricted at apex, limb 6.5–7 × 5–5.5 mm, elliptical, base truncate, margin fimbriate, the fimbriae longer and narrower distally, the basalmost stout and gland tipped, irregularly dentate at apex. Filaments connate in basal 1/4, tomentose distally, 1.5–3.5 mm long, shortest opposite posterior petal, longest opposite anterior sepal, those opposite posterior-lateral petals much stouter than all others; anthers tomentose at base and with scattered hairs distally and at apex, those opposite sepals 1.7–2 mm long, the connective slightly exceeding the locules, those opposite petals 1.6–2 mm long, the connective not exceeding the locules. Ovary 1–1.8 mm long; styles nearly terete, apex dorsally acute, the proximal 1/3 to 1/2 hirsute, 3.7–4 mm long, the posterior slightly longer than the anterior, anterior style nearly straight and erect or inclined slightly towards posterior petal, posterior styles lyrate. Samara not seen.

Mezia bahiana has been collected only once in disturbed ‘mata higrófila’ of Bahia, Brazil (Fig. 1). It is the only species in which the large leaf glands are placed on the petiole instead of the base of the lamina. The only other species occurring in non-Amazonian Brazil is Mezia araujoi (Espírito Santo, eastern Minas Gerais, and Rio de Janeiro). It shares with Mezia bahiana the lyrate posterior styles and may have the basal leaf glands partly on the petiole but lacks the large gland on the outer bracteole.

Fig. 7.

Mezia beckii. A, Large leaf, abaxial view. B, Enlargement of abaxial surface of lamina. C, Glands at base of lamina, abaxial view. D, Portion of inflorescence. E, Umbel of flower buds. F, Flower subtended by bracteoles (note gland on one bracteole), anterior sepal in centre, petals removed. G, Flower seen from below, posterior petal at top. H, Flower in face view, posterior petal at top. I, Posterior petal, abaxial view. J, Androecium, abaxial view, stamen fifth from left opposite posterior petal. K, Anthers, adaxial view, opposite sepal (left) and opposite petal (right). L, Gynoecium, anterior style at left. M, Distal portion of style. N, Samara, abaxial view. O, Detail of adaxial view of samara, showing areole and surrounding winglets. Scale bar equivalents: A, 4 cm; B and C, 8 mm; D, 4 cm; E, 1.3 cm; F–H, 8 mm; I, 5.7 mm; J, 3.3 mm; K, 2.7 mm; L, 3.3 mm; M, 1.7 mm; N and O, 4 cm. Based on: A–M, Beck et al. 19513 (MICH); N and O, Jardim 2397 (MICH). Drawn by Karin Douthit.

Woody vine to 20 m; stems sericeous when young, eventually glabrescent, youngest axes flattened or quadrangular, soon becoming terete. Lamina of leaves 11.5–23 × 7.2– 10.3 cm, elliptical or slightly obovate, apex abruptly short-acuminate with the acumen 5–10 mm long, base cuneate, margin slightly thickened and flat, glabrous at maturity or abaxially seemingly glabrous but with minute scattered hairs to 0.3 mm long, abaxially bearing a pair of large glands at base sunk in crypts or eglandular, with 0–4 small impressed glands within each margin distally, costa and 4 or 5 pairs of principal lateral veins and reticulum slightly prominulous adaxially, prominent abaxially; petiole 15– 26 mm long, glabrate; stipules caducous. Inflorescence multibranched, some lateral axes subtended by 1 or 2 additional floriferous axes; stalk of the lateral umbels 5–14 mm long, bearing 1 pair of caducous eglandular sterile bracts 2–2.5 mm long at or near base; floriferous bracts caducous (only one seen), 4.3 mm long, obovate conduplicate, apex broadly rounded, adaxially glabrous; peduncle 11–18 mm long in flower and fruit, notably thickened in fruit; bracteoles 5–7.5 mm long, adaxially glabrous, apex broadly rounded and often emarginate, midrib not raised abaxially, the outer bearing 1 prominent circular or elliptical gland 0.5–1 mm long abaxially at base near one margin, the inner eglandular, persistent past maturity of fruit, pedicel c.1 mm long in flower, to 2 mm long in fruit. Sepals 4.5–5.5 mm long beyond glands, 2–2.5 mm wide, spatulate, laterally revolute, abaxially densely brown-tomentose, the anterior eglandular, the lateral 4 biglandular, glands completely connate, 2.3–2.5 mm long, the pair 1.8– 2.3 mm wide, obovate or quadrate. Lateral petals yellow, abaxially white-tomentose in centre of limb, margin erose, base of limb acute or truncate, claw of anterior-lateral petals c.3 mm long, limb c.11–12 × 8–9 mm, obovate, claw of posterior-lateral petals c.2.5 mm long, limb 7–7.5 mm in diameter, orbicular; posterior petal yellow, perhaps red in centre, abaxially white-tomentose in centre of limb, claw 1.6–7 mm long, constricted at apex, limb c.6 × 4.7–5 mm, broadly ovate to suborbicular, base cordate, margin dentate or short-fimbriate, eglandular. Filaments connate only in the basal 0.6 mm, tomentose distally, 2–4 mm long, shortest opposite posterior and anterior-lateral petals, longest opposite anterior-sepals, those opposite posterior-lateral petals somewhat stouter than all others; anthers 1.5–2 mm long, tomentose at base and along locules, those opposite the sepals more abundantly so than those opposite petals, the connective not exceeding the locules or very slightly so only in anthers opposite sepals. Ovary 1.5 mm long; styles 3–3.5 mm long, nearly terete, apex pedaliform and extended into a tiny spur, sericeous at base, anterior style nearly straight and erect or inclined slightly towards posterior petal, posterior styles lyrate. Samara 65–85 mm in diameter, suborbicular, wings thinly sericeous; lateral wing 25–35 mm wide, continuous at base, deeply incised at apex to where both lobes fuse with proximal 5–10 mm of central dorsal wing, membranous, nearly flat except near nut, entire or repand at margin; central dorsal wing 23–32 × 7–15 mm, semicircular or somewhat repand, connected to lateral wing on each side by 5–7 interconnected winglets; nut 10–15 mm long, appressed-tomentose, adaxially with a series of ribs radiating from areole, some ribs developing into winglets adnate to underside of lateral wing and sometimes also connate basally with each other to produce a crest or winglet parallel to the lateral wing; areole 11–12 × 4 mm, narrowly ovate; torus c.3 mm high.

Distribution and habitat

Bolivia (Pando) and Brazil (Acre); in wet forest; one collection from 180 m. Figure 1.

Mezia beckii is the only species of Mezia reported from Bolivia. The lyrate styles and the outer bracteole with a large gland separate it from all other Amazonian species of Mezia except M. mariposa. The latter differs in its glabrous petals and a butterfly-shaped samara.

Fig. 8.

Mezia rufa and M. curranii. A–G, M. rufa. A, Leaf, abaxial view. B, Portion of inflorescence. C, Flower bud enclosed by bracteoles. D, Flower, posterior petal at top. E, Anther opposite petal, lateral view. F, Anther opposite sepal, lateral view. G, Gynoecium, anterior style in centre. H and I, M. curranii. H, Leaf, adaxial view. I, Samaras, abaxial view (left) and adaxial view (right). Scale bar equivalents: A and B, 4 cm; C, 8 mm; D, 1.3 cm; E and F, 2 mm; G, 4 mm; H and I, 4 cm. Based on: A–G, Silva & Brazão 60837 (MICH); H and I, Curran 253 (MICH). Drawn by Karin Douthit.

Woody vine; stems sericeous when young, soon glabrate, young axes quadrangular or flattened, soon becoming terete. Lamina of larger leaves 12.5–23 × 4.5–8.3 cm, elliptical or narrowly obovate, apex acuminate with the acumen 15–20 mm long, base briefly attenuate, margin thickened and flat or slightly recurved, adaxially glabrous, abaxially glabrous or sprinkled with minute straight appressed hairs to 0.4 mm long (glabrous to the naked eye), abaxially bearing 2 large glands at the base sunk into crypts, with a row of 5–10 tiny impressed glands within each margin, costa flush adaxially and prominent abaxially, c.6 or 7 pairs of principal lateral veins and reticulum prominulous adaxially and prominent abaxially; petiole 12–17 mm long, glabrate at maturity; stipules caducous. Inflorescence terminal and axillary, multibranched, some lateral axes subtended by an additional floriferous axis; stalk supporting lateral umbels 5–7 mm long, with 1 pair of caducous sterile bracts (not seen) at about the middle; floriferous bracts not seen; peduncle 7–9 mm long in fruit; bracteoles (only 2 seen) c.6 mm long, adaxially glabrous, apex rounded or bifid, midrib not raised abaxially, eglandular, apparently not persistent past maturity of fruit; pedicel to 1.5 mm long in fruit. Sepals 6–6.5 mm long beyond glands, 1.5–1.8 mm wide, spatulate, laterally revolute, abaxially densely light-brown tomentose, the anterior eglandular, the lateral 4 biglandular, glands compressed but distinct, each 2–2.5 × 1.1 mm, obovate. Petals not seen. Filaments glabrous, connate for about 1/2 their length except those opposing the posterior-lateral and posterior petals c.3/4 connate, 2–2.7 mm long, shortest opposite posterior petal, then progressively longer opposite anterior-lateral petals, lateral sepals and posterior-lateral petals (these 2 much stouter than all the others), longest opposite anterior sepal; anthers opposite sepals densely tomentose, 1.5–2 mm long, the connective exceeding the locules up to 0.5 mm, anthers opposite lateral petals glabrous except for a few hairs at apex, 1.3–1.6 mm long, the connective not exceeding the locules, anther opposite posterior petal not seen, probably much smaller than others. Ovary 1.5 mm long; styles in fruit straight, terete, apex dorsally truncate, sericeous in proximal 1/3 to 1/2, anterior style 2.2–2.3 mm long, posterior styles 3.2–3.3 mm long. Samara 40–60 mm in diameter, suborbicular, wings sparsely sericeous to glabrate; lateral wing 20–30 mm wide, semicircular, continuous at base, incised at apex to the nut, membranous, margin repand; central dorsal wing 19–24 × c.7 mm, semicircular, with 1 lateral dorsal winglet on each side and parallel to central dorsal wing, 5–7 mm wide, with c.5–10 winglets intermediate between lateral wings and dorsal winglet, undulate, sometimes transverse; nut 6–7.5 mm long, sericeous, adaxially with a series of often shallow ribs radiating from the areole; areole 6–7 × 2.3–3 mm, narrowly ovate; torus 2–3 mm high.

Mezia curranii is known only from the two fruiting specimens that constitute the type collection gathered in Amazonas, Venezuela (Fig. 1). It differs from Mezia includens in its pubescent anthers, shorter styles and smaller samaras. The other species recorded from southern Venezuela are Mezia huberi and M. rufa, which differ most notably with their abaxially densely brown-sericeous laminas.

Fig. 9.

Mezia fanshawei C.E.Anderson. A, Leaf, abaxial view. B, Base of lamina, abaxial view. C, Umbel flower buds (one removed). D, Lateral petal, abaxial view. E, Posterior petal, abaxial view. F, Anther opposite sepal, front and side views. G, Anther opposite petal, front and side views. H, Gynoecium, anterior style in centre. A, 1 cm; B, 2.5 mm; C, 3 mm; D and E, 2.2 mm; F and G, 0.6 mm; H, 2 mm. Based on Fanshawe 2698 (NY). Drawn by John Megahan.

Woody vine; young stems sericeous, soon glabrate, young axes quadrangular, becoming terete. Lamina of larger leaves 8.5–c.16 × 3–7 cm, elliptical, apex acuminate with the acumen 7–10 mm long, base briefly attenuate, margin thickened and recurved, adaxially and abaxially glabrous, abaxially bearing a pair of large glands at base sunk into crypts, with 1–3 additional small impressed glands within each margin, costa and c.4–6 pairs of principal lateral veins impressed or flush adaxially and prominent abaxially, reticulum prominulous adaxially and prominent abaxially; petiole 8–11 mm long, glabrous; stipules caducous. Inflorescence terminal and axillary, multibranched, lateral axes apparently not subtended by an additional floriferous axis; stalk supporting lateral umbels 11–14 mm long, with 1 pair of deciduous eglandular sterile bracts 4–5.5 mm at about the middle to distal 1/4; floriferous bracts 8.5–9 mm long, broadly elliptical, concave, apex broadly rounded, adaxially glabrous, deciduous during anthesis; peduncle 11–13 mm long in flower and fruit, thickened in fruit; bracteoles 8.5–9 mm long, adaxially glabrous except for scattered hairs near the margin, apex broadly rounded to bifid, eglandular, midrib not raised abaxially, persistent past anthesis; pedicel to 1.5 mm long, to 3 mm in fruit. Sepals 3–4 mm long beyond glands, 1(–1.3) mm wide, narrowly oblong, laterally somewhat revolute, abaxially densely brown-appressed-hirsute, the anterior eglandular, the lateral 4 biglandular, the glands connate but free near apex, 3–3.5 mm long, the pair c.3 mm wide, obovate to quadrate. Lateral petals yellow, abaxially white-sericeous in centre of limb, subequal, claw c.2.5 mm long, the limb 7.5–8 mm in diameter, orbicular, base briefly truncate, margin of anterior-lateral pair erose, margin of posterior-lateral pair coarsely fimbriate proximally and denticulate-fimbriate towards apex; posterior petal yellow, perhaps tinged with red in centre, glabrous, claw c.3 mm long, thick, constricted at apex, limb c.6 mm in diameter, orbicular, base deeply auriculate, margin glandular-fimbriate, coarsely so at apex, glabrous. Filaments opposite sepals densely tomentose in distal c.1/3, those opposite petals glabrous, connate in basal 1/2 except those opposing posterior-lateral sepals and posterior petal 3/4 connate, 2–2.8 mm long, shortest opposite anterior-lateral and posterior petals, longest opposite sepals, almost as long as those opposite the 2 posterior-lateral petals and much stouter than the others; anthers densely tomentose, those opposite sepals 1.5–1.7 mm long, the connective exceeding the locules by 1–1.3 mm, those opposite petals 0.8–1.2 mm long, the connective barely exceeding the locules or up to 0.2 mm, that opposite posterior petal the smallest. Ovary 1.5 mm long; styles straight, terete or slightly flattened, apex dorsally acute or truncate, sericeous in the proximal 1/2, anterior style c.2 mm long, posterior styles c.2.5 mm long. Samara: mature not seen; immature samara subcircular, the lateral wing continuous at base, incised at apex to the nut, with additional interconnected winglets between central dorsal wing and lateral wing, nut adaxially apparently without ornamentation.

Etymology

Mezia fanshawei is named for the British botanist Dennis Basil Fanshawe (1915–1993), whose many collections from Guyana include the type.

Mezia fanshawei is known only from the type collected in Guyana (Fig. 1). It is unusual in the genus in that the bracts and bracteoles are subequal instead of the bracts being much smaller than the bracteoles. Among species with erect styles and glabrous leaves, it is also notable for having short sepals, with the glands connate but free at the apex. The tomentose anthers separate it immediately from Mezia includens, the species with which it is most likely to be confused.

Fig. 10.

Mezia huberi. A, Fruiting branch. B, Base of lamina, abaxial view. C, Umbel of flower buds (two buds removed). D, Flower, posterior petal at upper right, one posterior-lateral petal removed. E, Portion of lateral petal, abaxial view. F, Portion of posterior petal, abaxial view. G, Androecium, adaxial view, stamen fifth from right opposite posterior petal. H, Anthers, lateral view, opposite sepal (left) and opposite posterior-lateral petal (right). I, Gynoecium, anterior style at left. J, Samara, abaxial view (left), and in lateral view looking at apical notch (right), showing one winglet on each side of dorsal wing. Scale bar equivalents: A, 4 cm; B–D, 8 mm; E–G, 4 mm; H, 2 mm; I, 2.7 mm; J, 2 cm. Based on: A, B and J, Huber 4497 (MICH); C–I, Huber 449 (MICH). Drawn by Karin Douthit.

Shrub or small tree 2–8 m tall; stems densely and persistently brown-sericeous, young axes quadrangular, eventually terete. Lamina of larger leaves 9–18 × 5–12 cm, elliptical or somewhat obovate, apex abruptly short-acuminate with the acumen 5–9 mm long, base truncate or cuneate, margin notably thickened and slightly revolute, adaxially initially sericeous but soon glabrous (except proximally on and near costa), abaxially densely and persistently sericeous but the costa and major lateral veins glabrescent and sharply set off from surrounding surface, the hairs straight, appressed, up to 0.4 mm long, reddish or dark brown, abaxially bearing a pair of large glands at base sunk into crypts (flush in young leaves), with a row of small impressed glands within each margin, costa and 6–9 pairs of principal lateral veins impressed adaxially and prominent abaxially, the reticulum slightly prominulous adaxially and prominent abaxially; petiole 10–18 mm long, persistently sericeous; stipules caducous. Inflorescence probably terminal and axillary, multibranched, some lateral axes subtended by an additional floriferous axis; stalk of the lateral umbels 18–23 mm long, bearing 1 pair of deciducous sterile bracts at the middle to distal 1/3, each bract with a pair of glands near the base; floriferous bracts 4–5 mm long, obovate, concave, apex rounded, adaxially glabrous, deciduous during anthesis; peduncle 6–14 mm long in flower, to 22 mm in fruit and not or slightly thickened; bracteoles 7–9 mm long, adaxially glabrous or sparsely sericeous near margin, midrib not raised abaxially, eglandular, mostly persistent past maturity of fruit; pedicel 0.5–1 mm long in flower, to 5 mm long in fruit. Sepals 5–6 mm long beyond glands, 1.7–2 mm wide, spatulate, laterally revolute, abaxially densely tomentose, the anterior eglandular, the lateral 4 biglandular, glands compressed but distinct, each 3–3.8 × 1.3–1.7 mm, obovate or elliptical. Lateral petals yellow, abaxially sparsely white-tomentose or -sericeous in centre of limb, margin erose, subequal, claw 1.7–2 mm long, limb 9–11 mm in diameter, orbicular, base acute or truncate; posterior petal yellow, probably tinged with red in centre, glabrous, claw 3.5–4 mm long, constricted at apex, limb 5–7 × 4.5–6 mm, suborbicular, base auriculate, margin glandular-fimbriate or only dentate at apex. Filaments glabrous, connate for about 1/2 their length except those opposing the posterior-lateral sepal and posterior petal c.3/4 connate, 2–2.7 mm long, shortest opposite posterior and anterior-lateral petals, longest opposite anterior sepal, those opposite posterior-lateral petals somewhat stouter than all others; anthers glabrous, those opposite sepals 1.8–2 mm long, with the connective exceeding the locules by 0.3–0.9 mm, those opposite petals 1.2–1.5 mm long, the connective not exceeding the locules, that opposite the posterior petal the smallest. Ovary 1.3–1.5 mm long; styles straight, erect, laterally somewhat flattened, the proximal 1/3 to 1/2 sericeous, anterior style 2–2.5 mm long, apex dorsally truncate, the posterior styles 2.5–3 mm long, apex dorsally acute. Samara 30–40 mm in diameter, suborbicular, wings tomentose to loosely sericeous, more thinly on lateral wing; lateral wing 15– 18 mm wide, semicircular, continuous at base, incised to nut at apex, membranous, margin entire; central dorsal wing 7–11 × (3–)4–5 mm, semicircular, with 1 flat winglet 3– 4 mm high present on each side of and parallel to dorsal wing; nut 6–9 mm long, densely sericeous, without adaxial ornamentation; areole 6–7 × 4 mm, ovate; torus 4–5 mm high.

Distribution and habitat

Venezuela (Amazonas); open rocky savannas on sandstone slopes and in gallery forest; 150–550 m. Figure 1.

Mezia huberi differs from all other species in its habit and habitat. It is a dominant shrub with a dense crown in open rocky savannas on sandstone slopes and occasionally a small tree in a gallery forests (O. Huber, personal communication). The samara has the central dorsal wing flanked by one additional winglet on each side but lacks the profusion of winglets and crests found in many other species. This species also differs from all others in that the sterile bracts on the axis below the 4-flowered umbel each have a pair of glands near the base.

Fig. 11.

Mezia includens. A, Flowering branch. B, Base of lamina, abaxial view. C, Flower bud enclosed by bracteoles. D, Flower subtended by persistent bracteoles, petals removed, distal portion of anterior sepal cut away. E, Petals, abaxial view, posterior petal (left) and lateral petal (right). F, Androecium, abaxial view, stamen fifth from right opposite posterior petal. G, Stamens, adaxial view, opposite a sepal (above) and opposite a petal (below). H, Gynoecium, anterior style in centre. I, Apex of a posterior style. J, Samara, adaxial view. K, Detail of abaxial view of samara, showing dorsal wing flanked by intermediate winglets. Scale bar equivalents: A, 4 cm; B, 8 mm; C, 1 cm; D and E, 6.7 mm; F, 4 mm; G, 2.7 mm; H, 4 mm; I, 2 mm; J, 4 cm; K, 2 cm. Based on: A–I, Tillett et al. 45136 (MICH); J and K, Mori et al. 23727 (MICH). Drawn by Karin Douthit.

Woody vine to 40 m; stems sericeous when young, soon glabrous; young axes quadrangular, becoming terete. Lamina of larger leaves 13–22 × 6–11 cm, narrowly to broadly elliptical, sometimes slightly ovate or obovate, apex usually abruptly apiculate to short-acuminate with the acumen 5–15 mm long, base rounded to cuneate or slightly attenuate, margin thickened and flat, adaxially sericeous when very young but soon glabrous, abaxially sericeous when young but soon glabrescent, mature laminas appearing glabrous to the naked eye but commonly very sparsely sericeous or with some minute hairs retained especially along major veins and at or near base, the hairs straight, appressed, to 0.3(–0.4) mm long, barely or not touching, old laminas glabrous, abaxially bearing 2 large glands at the base flush or sunk into crypts, with a row or 1–3 tiny impressed glands within each margin, costa impressed adaxially and prominent abaxially, 4–6 pairs of principal lateral veins and reticulum mostly flush to prominulous adaxially and prominent abaxially; petiole 1.4–2.1(–2.5) cm long, sericeous to glabrate; stipules caducous. Inflorescence terminal and axillary, multibranched, some lateral axes subtended by an additional floriferous axis; stalk of the lateral umbels 6.5– 20 mm long, bearing 1 pair of deciduous eglandular sterile bracts 2.5–4 mm long in basal 1/4 to 1/3 or rarely near base; floriferous bracts 3–4.5(–5.5) mm long, obovate, concave, apex broadly rounded, adaxially glabrous or sericeous near apex, eglandular; peduncle 7–16(–20) mm long in flower, 11–25 mm long and notably thickened in fruit; bracteoles 8–12 mm long, adaxially varying from sericeous or only distally so and/or sparsely so or with hairs only near the margin or occasionally glabrous, commonly glabrous towards the centre and base, apex bifid, midrib not or slightly raised abaxially, eglandular, mostly persistent past maturity of the fruit; pedicel up to 2 mm long in flower and fruit, thickened in fruit. Sepals 6.5–9.5 mm long beyond glands, 2– 2.5 mm wide, spatulate, often laterally revolute, abaxially densely brown-tomentose, the anterior eglandular or sometimes biglandular, the lateral 4 biglandular, the glands compressed but distinct, each 2.5–3.5 × 1–1.5 mm, obovate. Lateral petals yellow, limb orbicular or broadly obovate, abaxially light-brown-sericeous in centre, margin erose, claw of anterior-lateral petals 1.5–2 mm long, limb 10–13 × 9–11 mm, claw of posterior-lateral petals 2.5–3 mm long, limb 14–16 × 12–14 mm; posterior petal yellow, tinged with red in centre, glabrous, claw 3.5–4.5 mm long, constricted at apex, limb 5–7.5 × 4–5.5 mm, broadly ovate, base auriculate or cordate, margin glandular-fimbriate. Filaments glabrous, connate for about 1/2 their length except those opposing the posterior-lateral and posterior petals c.3/4 connate, 2–4 mm long, shortest opposite posterior petal, longest opposite anterior sepal, those opposite posterior-lateral petals much stouter than all others; anthers glabrous, those opposite sepals 1.8–2.5 mm long, the connective exceeding the locules by 0.8–1.3(–1.5) mm, those opposite petals 1.1–2.2 mm long, the connective exceeding the locules 0–0.2 mm, that opposite the posterior petal the smallest. Ovary c.1.3 mm long; styles straight, terete or slightly flattened, apex dorsally acute or truncate, anterior style 3–3.5 mm long, the proximal 1/2 sericeous, posterior styles 4–5 mm long, the proximal 3/4 sericeous. Samara 70–115 mm in diameter, suborbicular, wings sparsely sericeous to glabrate; lateral wing 30–45 mm wide, semicircular, continuous at the base, incised to the nut at the apex, membranous, entire or repand at the margin; central dorsal wing 20–30 × 7–10 mm, semicircular, flanked on each side by an intermediate winglet connected to the lateral wing by a series of prominent ribs/crests and/or winglets; nut (8–)10–16 mm long, sericeous, without adaxial ornamentation to slightly ribbed; areole 7–12 × 3–6 mm; torus 2.5–4.5 mm high.

Distribution and habitat

Brazil (Amazonas), Colombia (Amazonas, Meta, Vaupés), Ecuador (Orellana), French Guiana, Guyana, Panama (Panamá, San Blas), Suriname, Venezuela (Amazonas, Bolívar, Carabobo); in moist and wet forest and in clearings; sea level to 900(–1400) m. Figure 1.

Mezia includens is recognised by the combination of glabrous leaves, lateral petals with light brown hairs abaxially, glabrous stamens, stout straight styles, and large samaras with intermediate winglets flanking the central dorsal wing. The young laminas are abaxially sericeous but with expansion soon become glabrescent, and mature laminas are usually glabrous or retain a few hairs, especially near the costa and veins. Occasionally the vesture is more tardily shed, and some larger laminas may be very sparsely sericeous abaxially. Among the glabrous-leaved species with erect straight styles, Mezia includens is immediately separated from M. andersonii, M. curranii, M. fanshawei and M. russellii by its glabrous androecium. The anthers of Mezia peruviana bear a very few hairs that may be overlooked; its shorter sepals have distinct to connate glands, and the hairs on the petals are white. Mezia includens is the most widespread species in the genus, occurring from Amazonia as far north as Panama. It has not been recorded reliably from Peru; however, it is possible that one or more of the sterile gatherings listed below under Undetermined Records belong to Mezia includens.

Bentham's and Turczaninow's epithets refer to the two huge bracteoles enclosing the flower bud until anthesis. Although it is not the type of Mezia, M. includens was the first species described from fertile material that showed those peculiar bracteoles.

Fig. 12.

Mezia mariposa. A, Flowering branch. B, Base of lamina, abaxial view. C, Umbel of flower buds. D, Flower bud enclosed in bracteoles; outer bracteole with gland. E, Flower subtended by bracteoles, posterior petal at upper right, two lateral petals removed. F, Lateral sepal, abaxial view. G, Posterior petal, abaxial view. H, Androecium, adaxial view, stamen fifth from left opposite posterior petal. I, Anther opposite sepal, lateral view. J, Anther opposite posterior-lateral petal, abaxial view. K, Gynoecium, anterior style in centre. L, Samara, abaxial view. M, Samara, adaxial view. Scale bar equivalents: A, 4 cm; B and C, 8 mm; D, 4 mm; E, 8 mm; F, 5 mm; G, 8 mm; H, 4 mm; I–K, 2.7 mm; L and M, 4 cm. Based on: A–K, Prance et al. 6633 (MICH); L and M, Prance et al. 2586 (NY). Drawn by Karin Douthit.

Woody vine to 17 m; stems sericeous when young, very soon glabrate, young axes flattened or quadrangular, soon to eventually becoming terete. Lamina of larger leaves 13–22 × (5–)6–10.5(–12) cm, narrowly to broadly elliptical or somewhat ovate or obovate, apex abruptly short-acuminate with the acumen 9–17 mm long, base rounded or truncate or cuneate, margin not thickened and flat, adaxially and abaxially sericous when very young and soon glabrate to glabrous, abaxially bearing a pair of large glands at base sunk in crypts, with a single row of small impressed glands inside margin on distal 1/2 to 3/4, costa and 5–8 pairs of principal lateral veins and reticulum prominulous adaxially and prominent abaxially; petiole 8–14(–17) mm long, initially sericeous but very soon glabrate; stipules caducous. Inflorescence terminal and axillary, multibranched, some lateral axes subtended by an additional floriferous axis; stalk of lateral umbels 5–13 mm long, bearing 1 pair of persistent or deciduous eglandular sterile bracts well above middle to (usually) near the apex; floriferous bracts 1.5– 3.5 mm long, ovate, often concave or conduplicate, apex rounded, adaxially glabrous, eglandular, deciduous during or past anthesis; peduncle (9–)11–18 mm long in flower and fruit, thickened in fruit; bracteoles 5–8 mm long, adaxially glabrous or sparsely sericeous, apex broadly rounded or truncate, midrib not raised abaxially, the outer bearing 1 sunken or flush gland 0.5–1.1 mm long abaxially at base, the inner eglandular, persistent past maturity of fruit; pedicel 0–1 mm long in flower, up to 3 mm long in fruit. Sepals (4–)5–6.5 mm long beyond glands, 2–3.4 mm wide, spatulate or narrowly oblong, laterally strongly revolute, abaxially densely appressed-tomentose or subsericeous, the anterior usually eglandular (rarely biglandular), the lateral 4 biglandular, the glands distinct or partially to almost completely connate, 2–3.3 mm long, the pair 1.5–2.7 mm wide, quadrate or obovate. Lateral petals yellow, glabrous, base acute, margin erose, claw of anterior-lateral petals 2.5–3 mm long, limb 13–16 × 13–15 mm, obovate, claw of posterior-lateral petals 3–3.5 mm long, limb 9–12 mm in diameter, orbicular; posterior petal yellow, proximally red in the centre, glabrous, claw 2.7–3.5 mm long, constricted at apex, limb 7–9 × 5–9 mm, eliptical to orbicular, base cordate, margin proximally glandular- or eglandular-fimbriate, distally dentate-erose. Filaments connate in the proximal 1/4 except those opposing the posterior-lateral sepal and posterior petal 1/2 connate, those opposite sepals glabrous or sparsely pilose, those opposite petals glabrous, 1.8–4 mm long, shortest opposite posterior petal, longest opposite anterior sepal, those opposite posterior-lateral petals stouter than all others; anthers with the connective not exceeding the locules, those opposite sepals abundantly tomentose, 1.7–2 mm long, those opposing the petals glabrous or with a few hairs, 1.3–1.5 mm long, that opposite the posterior petal the smallest. Ovary 1.5–1.8 mm long; styles flattened distally, apex dorsally extended into a spur 0.1–0.3 mm long, sericeous in proximal c.1/4, anterior style 2.5–3.2 mm long, straight and erect or inclined slightly towards posterior petal, posterior styles 3–4 mm long, lyrate. Samara 56–70 mm in diameter, butterfly-shaped, oblate, wings thinly short-tomentose to subsericeous, often patchily so; lateral wings 22–33 mm wide, dissected to nut at base and apex, roughly trapezoidal but rounded at base and obtuse at apex, relatively firmly membranous or subcoriaceous, margin entire or repand; dorsal wing 18–28 × 7–12 mm, crescent-shaped or triangular or rectangular, usually widest near apex, without winglets or other outgrowths between dorsal and lateral wings; nut 14–17 mm long, densely short-tomentose or subsericeous, without adaxial ornamentation; areole 10–13 × 4–6 mm, elliptical or obovate; torus 2–3 mm high.

Distribution and habitat

Brazil (Acre, Amazonas, Pará, Rondônia) and Peru (Huánuco); in high terre firme forests; to 400 m. Figure 1.

Mezia mariposa is unique in the genus in its butterfly-shaped samara, for which it is named. It is also notable for its glabrous petals; in all other species at least the lateral petals are pubescent. It is one of the five species with lyrate posterior styles, and among these has a gland on the outer bracteole, like Mezia bahiana and M. beckii.

Fig. 13.

Mezia peruviana C.E.Anderson. A, Leaf, abaxial view. B, Detail showing basal glands. C, Distal portion of inflorescence with umbels in bud. D, Anterior-lateral petal, abaxial view. E, Posterior-lateral petal, abaxial view. F, Posterior petal, abaxial view. G, Androecium, abaxial view, fourth stamen from left opposing posterior petal. H, Anther opposite sepal, front view. I, Anther opposite petal, front view. J, Gynoecium, anterior style in centre. Based on: A–C and G–I, Revilla 3659A (MICH); D–F, Tessmann 4564 (G). Drawn by John Megahan.

Woody vine; stems sericeous when young, eventually glabrous, young axes flattened, eventually becoming terete. Lamina of larger leaves 9.3–18.5 × 2.8–6.5(–13) cm, lanceolate to narrowly elliptical to broadly elliptical in very large leaves, in the smaller leaves near inflorescence often linear-lanceolate, apex acuminate with the acumen to 15(–20) mm long, base attenuate and shortly decurrent, margin thickened and flat, adaxially glabrous, abaxially appearing glabrous to the naked eye but sprinkled with minute widely spaced straight appressed brown hairs to 0.2 mm long, glabrous at maturity or retaining some hairs on the costa or near the base, large glands borne abaxially at base of lamina varying from 0 to 2, sunk in crypts, with 1–3 or a row of small impressed glands within each margin mostly in the distal 1/2, costa slightly impressed adaxially and prominent abaxially, 5–7 pairs of principal lateral veins and reticulum not or slightly prominulous adaxially and prominent abaxially; petiole 0.6–1.2(–2) cm long, glabrous; stipules caducous. Inflorescence terminal and axillary, multibranched, lateral axes sometimes subtended by an additional floriferous axis; stalk of the lateral umbels 5–8 mm long, bearing 1–3 pairs of caducous eglandular sterile bracts c.0.5 mm long (seen only at the very youngest umbels); floriferous bracts caducous (seen only at the very youngest umbels), 2.2–2.5 × c.1.5 mm, obovate, apex broadly rounded, conduplicate, adaxially glabrous; peduncle 6–13 mm long in flower; bracteoles 8–10 mm long, adaxially sparsely but evenly sericeous, apex bifid, the midrib not or slightly raised abaxially, eglandular; pedicel 1–1.5 mm long in flower. Sepals 5– 6 mm long beyond glands, 1.8–2 mm wide, spatulate, laterally revolute, abaxially densely brown-tomentose, the anterior eglandular, the lateral 4 biglandular, glands distinct or proximally to entirely connate, 2.8–3 mm long, the pair 2.1–2.5 mm wide, obovate or quadrate. Lateral petals yellow, abaxially sparsely white-sericeous in centre of limb and on claw, limb orbicular, margin erose to irregularly denticulate; claw of anterior-lateral petals c.3 mm long, limb c.16 mm in diameter, base acute; claw of posterior-lateral petal c.2.5 mm long, limb c.15 mm in diameter, base decurrent; posterior petal yellow, probably red in centre, glabrous, claw c.2 mm long, thick, constricted at apex, limb 8–9 mm in diameter, suborbicular, base truncate, margin irregularly denticulate-fimbriate, teeth/fimbriae gland-tipped decreasing in size from base of limb towards apex, the distalmost sometimes eglandular. Filaments glabrous, connate for 1/4 to 1/3 their length except those opposing the posterior-lateral and posterior petals 2/3 to 3/4 connate, 1.1–3.5 mm long, shortest opposite posterior petal, longest opposite anterior sepal, those opposite posterior-lateral petals much stouter than all others; anthers usually with a few scattered hairs, those opposite sepals 1–2.1 mm long, the connective exceeding the locules by 0.4–1(–1.3) mm, those opposite petals 0.8–2 mm long, the connective exceeding the locules by 0.3–0.6 mm. Ovary 1.3–2 mm; styles straight, terete or slightly flattened, apex dorsally acute, sericeous in proximal 1/2 to 3/4, anterior style 2–2.9 mm long, posterior styles 2.8–3.3 mm long. Samara not seen.

Distribution and habitat

Peru (Amazonas, Loreto); wet forest, 135–450 m. Figure 1.

Mezia peruviana differs from other species with glabrous or very sparsely sericeous laminas by its androecium. The anthers all bear a few scattered hairs, unlike Mezia includens with all glabrous anthers, and M. andersonii, M. curranii and M. russellii, all with abundantly hairy anthers.

The Tessmann collections, cited by Niedenzu in the protologue, were distributed by B in 1926 with a printed label with identical information, “Ost-Peru: Stromgebiet des Maranon von Iquitos aufwärts bis zur Santiago-Mündung am Pongo de Manseriche, ca. 77°30 West”. The photograph (F-negative 12715) of the B duplicate of Tessmann 4931 shows the original label with the data given above. No photograph exists of the original label of the B duplicate of Tessmann 4564. The collection Rimache Y. 6749 is placed here with some hesitation. The inflorescences show major insect damage; however, anthers dissected from buds all show scant hairs. The largest leaf measurements are taken from this specimen.

Woody vine to 38 m; stems sericeous when young, eventually glabrate, young and mature axes quadrangular and often bearing 4 narrow winglets, the latter lost with age. Lamina of larger leaves 16–28 × 10–17 cm, broadly elliptical or slightly ovate or obovate, apex abruptly acuminate with the acumen 10–20 mm long, base rounded or short-attenuate, margin thickened and flat or recurved in oldest, adaxially initially sericeous but soon glabrate to glabrous, abaxially densely and persistently sericeous, the hairs straight, appressed, up to 0.4 mm long, reddish or rust-coloured but fading to translucent with age, abaxially bearing a pair of large glands at base sunk into crypts (flush in young leaves) and commonly with 1–4 additional somewhat smaller glands, with a row of small impressed glands within each margin, especially distally, costa and 6–8 pairs of principal lateral veins impressed adaxially and prominent abaxially, the reticulum slightly prominulous adaxially and prominent abaxially; petiole 2– 2.5 cm long, sericeous or eventually glabrate; stipules caducous. Inflorescence terminal and axillary, multibranched, lateral axes often subtended by an additional floriferous axis; stalk of the lateral umbels (8–)1–18 mm long, bearing 1 pair (rarely 2 pairs) of deciducous eglandular sterile bracts in basal 1/4 to 1/3 or at or near base; floriferous bracts 4–6 × 4–4.5 mm, obovate, concave, apex broadly rounded, adaxially sericeous along margin and often also in distal 1/2; peduncle 11–15 mm long in flower, to 20 mm in fruit and notably thickened; bracteoles 10–12 mm long, adaxially sericeous (sometimes sparsely so) but glabrous near base, apex rounded or bifid, midrib not raised abaxially, eglandular, mostly persistent past maturity of fruit; pedicel up to 1 mm long in flower, to 3 mm in fruit. Sepals 6–7.5 mm long beyond glands, 2–3 mm wide, spatulate, laterally revolute, abaxially densely tomentose, the anterior eglandular, the lateral 4 biglandular, the glands compressed but distinct, each 3–4 × 1.5 mm, elliptical or obovate. Lateral petals yellow, claw 1.5–3 mm long, limb 10–16 × 9–14 mm, suborbicular, base acute or briefly truncate, abaxially white-sericeous in the centre, erose; posterior petal yellow, probably tinged with red in centre, glabrous, claw 4–5 mm long, thick, constricted at apex, limb 7–8 × 7–9 mm, suborbicular, base auriculate, margin glandular-fimbriate or distally eglandular. Filaments glabrous, connate for about 1/2 their length except those opposing the posterior-lateral sepal and posterior petal c.3/4 connate, 2.5–3.5 mm long, shortest opposite posterior petal, longest opposite anterior sepal, those opposite posterior-lateral petals much stouter than all others; anthers glabrous, those opposite the sepals 1.5–2.5 mm long, the connective exceeding the locules by c.0.5–1 mm, anthers opposite petals 1–1.8 mm long, the connective not or barely exceeding the locules, that opposite the posterior petal the smallest. Ovary c.1.3 mm long; styles straight, terete or slightly flattened, apex dorsally truncate or acute, the proximal 1/2 to 2/3 sericeous, anterior style 3–3.8 mm long, posterior styles 3.5–4.5 mm long. Samara c.60 mm in diameter, suborbicular, wings sparsely sericeous; lateral wing c.30 mm wide, semicircular, continuous at the base, incised to the nut at the apex, membranous, margin entire or repand; central dorsal wing 27–30 × 7.5–9 mm, semicircular, with a network of interconnected shorter parallel and transverse winglets between the dorsal and lateral wings; nut c.17 mm long, sericeous, adaxially without ornamentation or very slightly ribbed; areole c.16 × 5.5– 6 mm, narrowly ovate; torus c.4 mm high (?).

Distribution and habitat

Brazil (Amazonas), Peru (Loreto) and Venezuela (Amazonas, Bolívar); in moist to wet evergreen forest, along riverbanks; 50–400 m. Figure 1.

Mezia rufa, like M. huberi and M. sericea, has the abaxial surface of the lamina densely sericeous. The brown hairs apparently fade with age, the vesture becoming translucent but with some brown hairs sprinkled among the rest; to the casual observer, old laminas may appear glabrous. The samara of Mezia rufa is distinctive in the unusually large nut, c.17 mm long. The dorsal wing is not much shorter than the membranous lateral wings and about twice as wide as in Mezia sericea and M. huberi. Mezia sericea differs in its smaller bracts and bracteoles, the latter adaxially glabrous, smaller petals, and samara with chartaceous wings and a smaller nut and areole. Mezia huberi is a shrub or tree of savannas and gallery forests. Its samara lacks the dorsal network of winglets and has only one additional winglet between the central dorsal and the lateral wings.

Fig. 14.

Mezia russellii. A, Flowering branch. B, Base of lamina, abaxial view. C, Umbel of flower buds, the bracts and bracteoles not yet full sized. D, Flower subtended by bracteoles, the posterior petal at top. E, Calyx, anterior sepal in centre. F, Posterior-lateral petal, abaxial view. G, Posterior petal, adaxial view (left) and abaxial view (below). H, Androecium, abaxial view, stamen at left opposite anterior sepal. I, Anthers opposite sepal, abaxial view (left) and adaxial view (right). J, Anther opposite anterior-lateral petal, abaxial view (left) and adaxial view (right). K, Gynoecium, anterior style in centre. L, Distal portion of style, lateral view. M, Samara, abaxial view. N, Nut of samara in cross-section, with lateral wing truncated, showing one winglet on each side of dorsal wing. O, Ventral areole of nut of samara. Scale bar equivalents: A, 4 cm; B, 4 mm; C, 1.3 cm; D, 8 mm; E, 2.7 mm; F, 8 mm; G, 5.7 mm; H, 4 mm; I and J, 2.7 mm; K, 4 mm; L, 2.7 mm; M, 4 cm; N, 2 cm; O, 1.3 cm. Based on: A–L, Vásquez & Jaramillo 10301 (MICH); M–O, Vásquez & Jaramillo 10429 (MICH). Drawn by Karin Douthit.

Woody vine; stems sericeous when young, soon glabrate, young axes flattened, becoming terete. Lamina of larger leaves 14–18 × 7–10.5 cm, elliptical or slightly obovate, apex rounded and abruptly short-acuminate with the acumen 8–12 mm long, base broadly obtuse or rounded, margin thickened and slightly revolute, adaxially and abaxially glabrous at maturity (or with a few short appressed hairs on abaxial costa), abaxially bearing a pair of large glands at base sunk in crypts, with a row of c.5–7 small impressed glands within each margin on distal 1/2, costa mostly flush and prominent abaxially, c.5 pairs of principal secondary veins and reticulum prominulous adaxially and abaxially; petiole 13–17 mm long, sparsely sericeous to glabrate at maturity; stipules caducous. Inflorescence terminal and axillary, probably multibranched, some lateral axes subtended by an additional floriferous axis; stalk of the lateral umbels 8–12 mm long, sterile bracts apparently absent; floriferous bracts 7–8 mm long, broadly elliptical, deeply concave, apex broadly rounded at apex, adaxially glabrous; peduncle 11–12 mm long in flower, to 14 mm in fruit and thickened; bracteoles 9–12 mm long, adaxially glabrous or with a few scattered hairs, apex broadly rounded and often tearing down the middle in age, midrib raised, eglandular, persistent past maturity of fruit; pedicel c.1.3 mm long in flower, c.2.5 mm long in fruit. Sepals 1–2(–2.4) mm long beyond glands, 1–1.1 mm wide, spatulate, flat or laterally at most slightly revolute, abaxially hirsute, the hairs whitish or stramineous, the anterior eglandular, the lateral 4 biglandular, the glands compressed but distinct, each c.2.5 × 1–1.5 mm, obovate. Lateral petals yellow, limb obovate, base acute, abaxially white-sericeous in centre, margin glandular-fimbriate, claw c.2 mm long, limb of anterior-lateral petals 8–9 × 7–8 mm, limb of posterior-lateral petals 7–8 × 6–7 mm; posterior petal yellow, perhaps tinged with red in centre, glabrous, claw 3.3–3.5 mm long, thick, constricted at apex, limb 5–6 mm in diameter, orbicular, base deeply auriculate with the lobes overlapping abaxially (behind the claw), margin glandular-fimbriate. Filaments glabrous, all connate in the basal 1/2, 2.5–3.5 mm long, shortest opposite posterior petal, longest opposite anterior sepal, those opposite posterior-lateral petals much stouter than all others; anthers opposite sepals densely hirsute on locules, 1.7–2 mm long, the connective exceeding the locules by c.1 mm; anthers opposite petals bearing tufts of a few hairs at apex and/or base, the connective not exceeding the locules, those opposite posterior and anterior-lateral petals 1–1.2 mm long, those opposite posterior-lateral petals 1.8–2 mm long, that opposite the posterior petal the smallest. Ovary 1.5 mm long; styles straight, nearly terete, apex rounded, anterior style c.2 mm long, sericeous in proximal 1/2, posterior styles c.2.5 mm long, sericeous only at base. Samara 67–90 mm in diameter, orbicular or somewhat oblate, wings finely and tightly brown-sericeous; lateral wing 30–40 mm wide, continuous at base, deeply incised at apex to where both lobes fuse with central dorsal winglet, membranous, entire or repand at margin; central dorsal wing 25 × 8–10 mm, roughly semicircular, flanked by 2 parallel dorsal winglets, connected to lateral wing by a mass of irregular ruffles; nut 12–13 mm long, densely brown-sericeous, adaxially without ornamentation; areole 11–12 × 4.5 mm, narrowly ovate; torus c.3 mm high.

Distribution and habitat

Peru (Loreto); primary forest; 122–150 m. Figure 1.

Mezia russellii is distinguished by its short flat sepals with straight whitish hairs and the auriculate posterior petal with the lobes overlapping behind the claw. Also notable are the large bracts; in other species, except Mezia fanshawei, the bracts are much smaller than the bracteoles. The short styles are all apically rounded; the only other species with presumably all styles apically blunt is Mezia tomentosa, which differs in its velutinous abaxial laminar vesture.

Two fruiting specimens, collected by Ducke at Iquitos and deposited at MG (MG7478), are labelled “Mascagnia macrocarpa Huber”, a name that was never published. We saw only photographs (F negative 45546) and online images (Reflora Herbário Virtual, no date). These specimens appear to belong to Mezia russellii, but this determination must be verified.

Fig. 15.

Mezia sericea C.E.Anderson. A, Leaf, abaxial view. B, Base of lamina, abaxial view. C, Distal portion of inflorescence with one flower open. D, Anterior-lateral petal, abaxial view. E, Posterior-lateral petal, abaxial view. F, Posterior petal, abaxial view. G, Anther opposite sepal. H, Anther opposite petal. I, Gynoecium, anterior style in centre. J, Samara, abaxial view. K, Detail of samara, abaxial view, showing dorsal wing flanked by additional winglets. L, Detail of samara, showing areole. Scale bar equivalents: A, 1 cm; B, 5 mm; C, 1 cm; D, 2.3 mm; E, 2 mm; F, 1.3 mm; G, 0.7 mm; H, 1.1 mm; I, 0.9 mm; J, 1.85 mm; K and L, 3.5 mm. Based on: A–I, Assunçao 784 (MICH); J–L, Ribeiro 1792 (MO). Drawn by John Megahan.

Woody vine to 12 m; stems sericeous when young, soon glabrous, young axes quadrangular, eventually becoming terete. Lamina of larger leaves 12.5–16 × 6– 7.5 cm, elliptical to obovate, apex usually abruptly short-acuminate at apex with the acumen 10–15 mm long, base attenuate and slightly decurrent, margin thickened and slightly recurved, adaxially glabrous, abaxially densely brown-sericeous, the hairs straight, appressed, up to 0.3 mm long, large glands borne abaxially at or near base of lamina varying from 0 to 4 (or 5), mostly sunk into crypts, with a row of small impressed glands within each margin, costa impressed adaxially and prominent abaxially, 4 or 5 pairs of principal lateral veins flush or slightly impressed adaxially and prominent abaxially, reticulum prominulous adaxially and prominent abaxially; petiole 2–3 cm long, sericeous; stipules caducous. Inflorescence terminal and axillary, lateral axes sometimes subtended by an additional floriferous axis; stalk of the lateral umbels 6–7.5 mm long, bearing 1 pair of deciduous eglandular sterile bracts c.1.5 mm long in proximal 1/4 to 1/3 or near base; floriferous bracts 3–3.5 mm long, obovate, concave, apex broadly rounded, adaxially glabrous, deciduous before or during anthesis; peduncle 11–13 mm long in flower and fruit, somewhat thickened in fruit; bracteoles 6.5–7.5 mm long, adaxially glabrous, apex rounded, the midrib not raised abaxially, eglandular, mostly persistent past maturity of fruit; pedicel c.0.5 mm long in flower, to c.2 mm in fruit. Sepals 5.5–5.7 mm long beyond glands, c.2 mm wide, spatulate, laterally revolute or flat, abaxially densely brown-tomentose, the anterior eglandular, the lateral 4 biglandular, glands compressed but distinct, each 2.2–2.3 × 0.8–1 mm, obovate. Lateral petals yellow, abaxially white-sericeous in the centre of limb, base acute or briefly truncate, margin erose; claw of anterior-lateral petals c.2.5 mm long, decurrent, limb c.11–12 mm in diameter, orbicular, claw of posterior-lateral petals c.2 mm long, limb c.8 × c.7 mm, broadly elliptical; posterior petal yellow, tinged with red in centre, glabrous, claw c.3 mm long, thick, constricted at apex, limb 5–5.5 × 4.5–5 mm, broadly obovate, base truncate or slightly cordate, margin glandular-fimbriate to glandular-dentate at apex. Filaments glabrous, connate for c.1/3 their length except those opposing the posterior-lateral and posterior petals c.2/3 connate, 2–3 mm long, shortest opposite posterior petal, longest opposite anterior sepal, those opposite posterior-lateral petals much stouter than all others; anthers glabrous, those opposite sepals 1.2–2.5 mm long, the connective exceeding the locules by 0.2–1 mm, anthers opposite petals 1–2.2 mm long, those opposite the anterior-lateral and posterior petals with the connective exceeding the locules by 0.2–0.3 mm, those opposite the posterior-lateral petals with the connective equalling the locules, that opposite the posterior petal the smallest. Ovary c.1.3 mm long; styles straight, terete or slightly flattened, apex dorsally acute or truncate, anterior style 2.2–2.5 mm long, the proximal 1/2 sericeous, posterior styles 3.5–3.8 mm long, the proximal 1/3 to 2/3 sericeous. Samara 60–75 mm in diameter, suborbicular; wings sparsely sericeous; lateral wing 30–35 mm wide, semicircular, continuous at base, incised to the nut at the apex, chartaceous, margin entire or repand; central dorsal wing 8–9 × 4.5–7 mm, semicircular, with a network of shorter parallel and transverse winglets between the dorsal and lateral wings giving a ruffled appearance; nut 7–8 mm long, sericeous, adaxially slightly ribbed; areole 6.5–7.1 × 4–4.5 mm, ovate; torus c.3 mm high.

Distribution and habitat

Brazil (Amazonas) and Suriname; in forest; 100–200 m. Figure 1.

Mezia sericea differs from all other species except M. huberi and M. rufa in its leaves with abaxially sericeous laminas. It is separated from Mezia huberi in its vining habit and samaras bearing numerous winglets between the dorsal and lateral wings. The bracts and bracteoles of Mezia rufa are longer than those of M. sericea and adaxially sericeous, and the petals are larger. The samaras of Mezia rufa have membranous wings and a nut about twice as large as that of M. sericea. The fruiting collection from Suriname presents a considerable disjunction from the type locality; however, the samaras and bracteoles place it with Mezia sericea rather than M. rufa.

Fig. 16.

Mezia tomentosa. A, Samara, adaxial view. B, Samara, abaxial view. C, Detail of abaxial view of samara, showing network of dorsal wing and intermediate winglets. Scale bar equivalents: A and B, 4 cm; C, 1.3 cm. Based on Espinoza 244 (MICH). Drawn by Karin Douthit.

Woody vine to 20 m; young stems subsericeous or appressed-tomentose, eventually glabrate, young axes quadrangular, soon to eventually becoming terete. Lamina of larger leaves 11.5–17 × 5–9.4 cm, elliptical or slightly ovate or obovate, apex abruptly acuminate with the acumen 7–15 mm long, base cuneate, margin slightly thickened and somewhat revolute, adaxially probably initially hairy but at maturity glabrous (or tomentose proximally on midrib), abaxially densely and persistently velutinous or tomentose, the spreading vesture a mixture of V-, Y- or T-shaped dark brown hairs, sometimes unevenly abraded from oldest leaves, laminar glands apparently absent, costa and 5–8 pairs of principal lateral veins impressed adaxially and prominent abaxially, larger veins of reticulum slightly impressed adaxially and all prominent abaxially; petiole 15–23 mm long, densely sericeous, eventually glabrescent; stipules caducous. Inflorescence known only in late fruit, probably terminal and axillary, multibranched, additional floriferous axes not seen; stalk of lateral umbel 5–11 mm long, bearing 1 pair of deciduous sterile bracts in basal 1/4 or near base; floriferous bracts 4–4.5 mm long, elliptical or obovate, concave, apex rounded, adaxially glabrous, deciduous before maturation of fruit or persistent; peduncle 10–14 mm long in fruit; bracteoles 6–8 mm long, adaxially glabrous, apex truncate or somewhat emarginate, midrib sometimes raised abaxially, eglandular, mostly persistent past maturity of fruit; pedicel 1–2.5 mm long in fruit. Sepals 6.5–7.5 mm long beyond glands in fruit, 2.5– 3 mm wide, spatulate, laterally slightly revolute, abaxially densely brown-tomentose, the anterior eglandular, the lateral 4 biglandular, the glands compressed but distinct, each 1.5–2 × 1–1.3 mm, obovate. Petals not seen. Filaments c.1/2 connate, glabrous; anthers not seen. Ovary not seen; styles in fruit straight, terete or laterally flattened distally, 2.4–3.2 mm long, apex dorsally rounded or obtuse, the proximal 1/2 to 2/3 densely sericeous. Samara 7–9 cm in diameter, oblate to nearly circular, wings tomentose to subsericeous; lateral wing 30–43 mm wide, semicircular, continuous at base, incised to nut at apex, membranous, distally flat but strongly corrugated near nut, repand at margin; central dorsal wing and several intermediate wings indistinguishable, highly dissected and interconnected by transverse winglets, all c.8–10 mm high, together forming a ruffled complex of winglets of diverse orientations; nut tomentose, adaxially without ornamentation or very slightly ribbed; areole 7–10 × 2–3 mm, narrowly ovate; torus 2–3.5 mm high.

Distribution and habitat

Ecuador (Pastaza); wet primary tropical forests; 390–400 m. Figure 1.

Mezia tomentosa is immediately separated from all other species by the velutinous abaxial vesture on the lamina. The V-, Y- or T-shaped leaf hairs are unique in the genus; in all other species of Mezia the leaf hairs (if any) are sessile, straight and tightly appressed.