Introduction
A recent synopsis of the genus Rivea Choisy (Convolvulaceae) attempted to account for all names published in this genus (Staples, Reference Staples2007). One name that could not be satisfactorily resolved at that time was Rivea bernoulliana (Peter) Hallier f. Subsequently, further research has disclosed original material for this name in the herbarium in Göttingen (GOET), where Peter’s herbarium is preserved (Stafleu & Cowan, Reference Stafleu and Cowan1983), that allows us to lectotypify the names involved and make the necessary reduction. The names are needed for the forthcoming account of Convolvulaceae in Flora Mesoamericana (Austin et al., in press) so we are opting to publish this note now, although an account for all the Peter names in Convolvulaceae is under preparation and will be published in due course.
Ipomoea bernoulliana Peter in Engler & Prantl, Nat. Pflanzenfam. IV(3a): 30 (1891). – Rivea bernoulliana (Peter) Hallier f., Bot. Jahrb. Syst. 18: 158 (1893). – Type: Guatemala, inter S. Miguelito et fl. Nagualate, i 1878, Bernoulli & Cario 1902 (lecto GOET!, designated here).
Ipomoea santae-rosae Standl. & Steyerm., Publ. Field Mus. Nat. Hist., Bot. Ser. 23: 81 (1944). – Type: Guatemala, Dept. Santa Rosa, vicinity of Chiquimulilla, 29 xi–8 xii 1950, Standley 79287 (holo F!).
As noted in the synopsis of Rivea (Staples, Reference Staples2007), previous authors on the Guatemalan flora disregarded the Peter name as a nomen nudum. However, there is ample descriptive information in Peter’s differential diagnosis to validate the name and it has to be considered as validly published. Peter did not cite any specimens, merely noting the origin as Guatemala. The single specimen conserved in GOET (image available online at https://gwdu64.gwdg.de/pls/herbar/typen$typen.QueryViewByKey?P_ID=1387&Z_CHK=5332) seems highly likely to be original material for the Peter name because: (i) it is annotated by Peter himself with his new name (indicated on this label is ‘Peter scripsit’); (ii) the collector (Bernoulli) and country (Guatemala) are in agreement with the protologue; (iii) the collection date (1866–78) predates the publication of the Peter name by at least 13 years, so the specimen could have been available to Peter; and (iv) the morphology of the specimen itself corresponds almost exactly with the information contained in Peter’s differential diagnosis for the species. Furthermore, the GOET specimen was annotated by Hallier (dated 10.I.1893) with his combination in Rivea only two years after Peter published his name. In the aggregate, the evidence suggests this specimen was original material for Ipomoea bernoulliana Peter and we are therefore choosing this sheet as the lectotype for the name.
