New Taxa

Centaurium tenuiflorum (Hoffmanns. & Link) Fritsch subsp. anglicum T.C.G.Rich & McVeigh, subsp. nov.

Annual 7–30(–32) cm tall, erect, pale olive-yellowish green to bright green, turning orangey yellow when old, glabrous. Basal rosette usually withered at flowering but sometimes present (or sometimes poorly defined) with 1–3 pairs of leaves. Rosette leaves 2–10 × 1.5–8 mm, broadly elliptic to obovate, obtuse at apex, entire, 1-veined, broadly but shortly petiolate. Stems 4-angled, winged, simple or branched mainly above; middle internodes to 3–4 times as long as their leaves. Stem leaves 4–10(–14) pairs on main stem, sometimes overtopped by side branches with another pair of leaves, (3–)5–18(–22) × (1–)4–8(–15) mm, ovate to elliptical-ovate, (1.7–)2–5(–5.5) times as long as wide, obtuse or minutely mucronulate in larger plants, with base rounded and sessile to weakly cordate, entire, 3- to 5-veined, becoming narrower, acute and 1-veined up the stem. Inflorescence cymose, open and lax with a few flowers to dense with numerous flowers. Terminal pedicel (0–)1–8(–19) mm. Flowers 4- to 5-merous (often 4-merous in small plants or on lateral branches of big plants). Calyx (6–)7–10(–11) mm; calyx tube c.1 mm, funnel-shaped; calyx lobes 5–8 mm, linear to subulate, ridged, acute, appressed, ± equal or unequal in size, acute on angles but not winged. Calyx nearly as long as corolla tube. Corolla (10.5–)11.5–16(–16.5) mm; corolla tube (6–)8–12(–13) mm, cylindrical, not noticeably veined, slightly constricted towards to the top; corolla lobes 2.5–5(–6) × 1.5–2 mm, pink or white but slightly pink-flushed (not pure albino), elliptical, spreading, obtuse to rounded. Corolla 1.4–1.8(–2) times as long as calyx. Anthers yellow, c.0.5 mm, elliptic and twisted when dehisced, exerted. Filaments whitish, inserted just below top of corolla tube. Mean pollen size 24.5 µm (range, 22.8–25.5 µm). Ovary narrowly ellipsoid. Stigma 2-lobed, elongated, yellowish green. Capsule 8–11 mm, cylindrical, opening from apex; seeds c.0.4 mm, ovoid, brown.

Two subspecies of Centaurium tenuiflorum have been recognised in Europe, although there is an indication that three or even four taxa may be involved (Zeltner, Reference Zeltner1970; Melderis, Reference Melderis, Tutin, Heywood, Burges, Moore, Valentine, Walters and Webb1972a; Mansion et al., Reference Mansion, Zeltner and Bretagnolle2005; Tison & de Foucault, Reference Tison and de Foucault2014). Subspecies anglicum occurs in southern England (hence the epithet) in the Isle of Wight, where it occurs at the top of salt marshes, and in Dorset, where it occurs on damp, slumping, clay sea cliffs. The Isle of Wight material has pink flowers, and the Dorset material has nearly white flowers. It is presumed to have arisen through isolation and local adaptation following reflooding of the English Channel after the last Ice Age.

Biennial with linear-elliptic, 3-veined, acute middle-stem leaves 3.4–4.9 times as long as wide, calyx:corolla tube length ratio 0.65–0.75, corolla lobes c.5.5–5.6 mm, stigma lobes weakly cordate, largely infertile.

A new name is required for tetraploid hybrids between Centaurium erythraea and C. littorale which have been widely reported from coastal Northwest Europe. The hybrids are generally intermediate between the parents, often having the darker pink flowers of Centaurium littorale but the broader stem leaves of C. erythraea, and are usually tetraploid like both parents (Ubsdell, Reference Ubsdell1976b, Reference Ubsdell1979). They have been widely included in Centaurium × intermedium (Wheldon) Druce, but Ubsdell (Reference Ubsdell1979) showed that this name as used by Wheldon (Reference Wheldon1897) should be restricted to hexaploid plants from the South Lancashire coast which are treated as a genetically stable, fertile, self-sustaining, allopolyploid species. Fournier (Reference Fournier1938) coined the combination Centaurium × klattii for C. erythraea × C. littorale but provided no description; it is thus validated here.

Validating description (Wheldon & Salmon, Reference Wheldon and Salmon1925; p. 346): “Stem rather stout, 4–20 cm high much branched below with divergent branches. Lower part of stem very leafy with short internodes. Distinct basal rosette absent. Leaves similar in shape to Centaurium pulchellum but larger and in well-developed plants to 2–4 cm on the main stem. Flowers numerous in broad, fasciculately branched panicles, only the ultimate cymes truly dichotomous. Pedicels of main stem short (axillary flowers sessile or subsessile). Calyx about equalling corolla tube in length at anthesis, in ripe fruit 1/3–1/2 as long. Corolla lobes c.5 mm but variable, at anthesis as long as the tube, about half as long as tube in fruit. Fruits cylindrical, c.10 mm. Seeds 0.4–0.5 mm, irregularly angular, pitted”.

This hybrid is intermediate between the parents in all characters (Stace et al., Reference Stace, Preston and Pearman2015) but can be difficult to separate from depauperate Centaurium erythraea. Named in honour of Francis Ubsdell for the excellent work on British Centaurium.

Annual herb to 13(–17) cm, erect, glabrous, dark green to purple-flushed, simple or sparsely branched above or from base. Basal rosette leaves present at flowering, spathulate to lanceolate, 3-veined, obtuse, sessile or broadly petiolate. Stem 4-angled, usually dark or sometimes green. Stem leaves (0–)1–2(–3) pairs, (4–)6–28(–32) × (1–)2–9(–12) mm, lanceolate to ovate-lanceolate, 3-veined, acute to acuminate, sessile, (1.7−) 2–4.5(–5.5) times as long as wide. Inflorescence with 1–20 terminal and axillary flowers although often fewer than 5, 4- or 5-merous. Terminal pedicels (4–)6–22(–26) mm, to 60 mm on side branches. Calyx (5–)7–15(–17) mm; calyx tube 1–4 mm; calyx lobes 5–11 mm, usually markedly unequal in width, the widest lobe (1.1–)1.3–3.6(–4) times as wide as the narrowest lobe, some usually characteristically outcurved. Corolla (7–) 11–20 mm; corolla tube (4–)6–14 mm, ± cylindrical but slightly wider towards top, bluish purple to purplish pink; corolla lobes (3–)4–6(–9) mm, similar in colour to the tube, ovate, acute, with long whitish fringes. Corolla (1–)1.1–2.2(–2.4) times as long as the calyx. Stigma 2-lobed, ± sessile. Capsule c.10–11 mm, soon longer than corolla, cylindrical, opening at apex; seeds 0.7–0.8 mm, brown, more or less round.

Gentianella amarella subsp. occidentalis is characterised by being annual with 0–2 (–3) internodes (mean, 1.3), the terminal internode on average c.1.7 times the average internode length, the long terminal pedicel forming up to 70% of total plant height, and the calyx teeth very unequal in width and usually outcurved. In cultivation, subsp. occidentalis is a summer annual and retains its morphology.

Molecular studies by S. de Carvalho (University of Amsterdam, unpublished data, 2006) showed that Gentianella amarella subsp. occidentalis is genetically different from Swedish G. uliginosa. Molecular studies by Winfield et al. (Reference Winfield, Wilson, Labra and Parker2003) showed that British plants ascribed to Gentianella uliginosa were genetically part of G. amarella. Gentianella amarella subsp. occidentalis can be consistently separated from subsp. amarella, which is a biennial with (4–)5–10(–14) internodes and the terminal internode typically forming up to 20% of the stem height and has sepal lobes nearly equal in width and ± appressed to the corolla. Gentianella amarella subsp. anglica differs in being a winter annual or biennial with sepal lobes nearly equal in width and ± appressed to the corolla.

Gentianella amarella subsp. occidentalis occurs in dune slacks in South Wales and Devon. Plants from Scotland (Gulliver, Reference Gulliver1998) are dwarfed Gentianella amarella subsp. amarella, as may be the Derbyshire plant (Rich, Reference Rich1996). Pritchard (Reference Pritchard1959) reported hybrids between subsp. occidentalis and subsp. amarella (as G. amarella × uliginosa), but these have not been found in the field and the original vouchers are small subsp. amarella (ABD; see also Kay & John, Reference Kay and John1995).

New Combinations

Centaurium erythraea Rafn var. latifolium (Sm.) T.C.G.Rich, comb. et stat. nov.

Basionym: Erythraea latifolia Sm., Engl. Fl. 1: 321 (1824)

Wheldon & Salmon (Reference Wheldon and Salmon1925) suggested that it may have originated through crossing of Centaurium pulchellum with one of the small capitate forms of C. erythraea, which is supported by the small flowers and broad leaves, although Melderis (Reference Melderis1972b) regarded it as a mutant of C. erythraea. It is closer morphologically to Centaurium erythraea than Centarium × ubsdellii; as it has been extinct since 1871, it has not been possible to grow plants and apply modern taxonomic methods, although DNA analyses may be able to resolve this if the DNA can be extracted satisfactorily.

Gentianella amarella (L.) Börner subsp. anglica (Pugsley) T.C.G.Rich & McVeigh, comb. et stat. nov.

Basionym: Gentiana anglica Pugsley, J. Bot. (Lond.) 74: 167 (1936)

Various authors including T.C.G. Rich have regarded Gentianella anglica (Pugsley) E.F.Warb. as a species (Pugsley, Reference Pugsley1936; Pritchard, Reference Pritchard1959; Rich et al., Reference Rich, Holyoak, Margetts and Murphy1997), but molecular studies by Winfield et al. (Reference Winfield, Wilson, Labra and Parker2003) showed that it is part of G. amarella and indicated that it was of relatively recent origin. Here, the narrow concept of Gentianella anglica as lectotypified by Rich et al. (Reference Rich, Holyoak, Margetts and Murphy1997) is retained at subspecific rank for plants flowering in early summer with 1–3 internodes and the terminal internode contributing more than 40% to the stem height. Plants treated as the fertile hybrids between Gentianella amarella and G. anglica = G. × davidiana T.C.G.Rich (G. anglica subsp. cornubiensis N.M.Pritch.; Rich et al., Reference Rich, Holyoak, Margetts and Murphy1997) are now included in the variable G. amarella subsp. amarella.

Aria parviloba (T.C.G.Rich) Sennikov & Kurtto, comb. nov.

Basionym: Sorbus parviloba T.C.G.Rich, Watsonia 27: 306 (2009)

Karpatiosorbus parviloba (T.C.G.Rich) Sennikov & Kurtto, Memoranda Soc. Fauna Fl. Fenn. 93: 49 (Reference Sennikov and Kurtto2017)

Sennikov & Kurtto (Reference Sennikov and Kurtto2017) placed Sorbus parviloba under Karpatiosorbus based on the suggestion in Rich et al. (Reference Rich, Houston, Robertson and Proctor2010) that its parentage might be “possibly S. eminentiformis × S. × tomentella”. T.C.G. Rich considers this is no longer the case and regards it simply as part of the Aria (Sorbus) eminens group as shown in the conspectus of Rich et al. (Reference Rich, Houston, Robertson and Proctor2010). The new combination under Aria is therefore required.

Cotula sessilis (Ruiz & Pav.) Stace, comb. nov.

This combination is needed to reflect the current inclusion of Soliva in Cotula (Himmelreich et al., Reference Himmelreich, Breitwieser and Oberprieler2012).