Dioscorea alainii Raz, 2016

Raz, Lauren, 2016, Untangling the West Indian Dioscoreaceae: New combinations, lectotypification and synonymy, Phytotaxa 258 (1), pp. 26-48 : 28-29

1. Dioscorea alainii Raz , nom. nov. Rajania hastata L. (1753: 1032). Lectotype (designated here):— HAITI. Port-de-Paix. Bryonia fructu alato , foliis auriculatis Plumier (1693: Tab. 98). See notes below for more about the type locality

Rajania hastata var. angusta Knuth (1917: 222) . Lectotype (designated here):— DOMINICAN REPUBLIC. Barahona: La Loma, August, 1911, M. Fuertes 1037 ♂. (lectotype NY!, isolectotypes BM!, GH!, MO!, S!). Remaining former syntypes: DOMINICAN REPUBLIC. Barahona, July, 1910. Fuertes 576. GH!, NY!; HAITI. Without locality, 1890. Picarda 104. I was not able to locate specimens of the latter.

Rajania hastata var. euhastata Knuth (1917: 222) . Under article 26.3 of the Melbourne Code (2012), this name is rejected. The autonym R. hastata L. var. hastata is the correct formulation. Knuth was inconsistent in his application of the prefix “eu” to varietal names. It is unclear why he employed it in the cases of R. hastata L. and R. cordata L., but not in the case of Dioscorea polygonoides Humb. & Bonpl. ex Willd.

Rajania hastata var. incisa Knuth (1917: 222) . Lectotype (designated here):— HAITI. S. Michel to Marmelade, August 6, 1905, Nash & Taylor 1457 ♂ (lectotype NY!). Remaining former syntype: HAITI. Fessard, no date, Christ 1716 ♂. I was not able to locate a specimen.

Rajania hastata var. latior Knuth (1917:222) . Lectotype (designated here):— DOMINICAN REPUBLIC. Barahona, 50 m, May, 1910, M. Fuentes 36 (lectotype NY!, isolectotype US!). No type was designated in the original publication, but five syntypes were cited Knuth (1924). Remaining former syntypes: DOMINICAN REPUBLIC. Without locality, 1856, Mayerhoff 39 ♀ (n.v.); HAITI. Crete Sale, 1900, Buch 432 (n.v.); Plateau de la Crete a Pierrot, 1898, Picarda 1658 ♂ (n.v.); St. Suzanne, 1909, Christ 2128 ♀ (n.v.).

Rajania hastata var. triloba Knuth (1917:222) . Type:— DOMINICAN REPUBLIC. Constanza, 1887, Eggers 2284 (n.v.). As yet I have not been able to locate a specimen.

Notes: Endemic to Hispaniola. When Britton & Millspaugh (1920) designated R. hastata as the type species of Rajania , they did not cite any elements upon which the name could be based. Linnaeus in his protologue of R. hastata , cited two elements that could serve for lectotypification: one is a wretched specimen in the Clifford Herbarium at BM (Clifford 458, BM000647488) that is annotated in the lower left hand corner (without date or attribution) in what appears to be David Prain’s hand as “ R. microphylla ”. The determination is correct, and can be referred to the species renamed here as Dioscorea bahamensis . Linnaeus (1737: 458) wrote in reference to this plant, “Crescit in insula s. Dominga”, a locality inconsistent with the present day distribution of D. bahamensis , but the reference is most likely to Plumier’s writings (see below) rather than to the specimen in the Clifford Herbarium (C. Jarvis, pers. comm.). Given the true identity of the specimen, it is here rejected for lectotypification purposes.

The second element, the Plumier illustration, selected here as the Lectotype, is based on a plant that Plumier found growing in the vicinity of Port-de-Paix, on the “Isle S. Domingue” (= Haiti; Plumier 1693, p. 84). The figure is consistent with Linnaeus’ description, and unambiguously depicts the Hispaniolan species renamed here as D. alainii .

The varieties subsequently described by Knuth are not accepted, as they are based exclusively on variation in leaf outline, a highly plastic trait in this and many other West Indian Dioscorea species (see discussion under D. cordata ). This epithet honors Alain Liogier (Hermano Alain), prolific collector and author of the Flora of Hispaniola. He also made significant contributions to the Flora of Cuba.