Dioscorea cephalocarpa (Uline ex R.Knuth) Raz, 2016

Raz, Lauren, 2016, Untangling the West Indian Dioscoreaceae: New combinations, lectotypification and synonymy, Phytotaxa 258 (1), pp. 26-48 : 30-31

4. Dioscorea cephalocarpa (Uline ex R.Knuth) Raz , comb. nov. Rajania cephalocarpa Uline ex Knuth (1917: 221) . Lectotype (designated here):— CUBA. (Pinar del Rio), 1860–1864 Wright 1712 p.p. ♂ ♀ (lectotype S “3A”! (♀), isolectotypes B! (♂), BM “2A”! (♂), BREM “A”! (♀), GH “2A”! (♀), GH “2C”! (♂), HAC! (3 sheets ♀ & 1 ♂, elements to be specified), K “2A”! (♂), NY1 ! (♀), NY “2B”! (♂), S “1B”! (♂), S “1C”! (♀),US “2C”! (♂), US “2D”! (♀), YU “3A”! (♀).). Remaining former syntypes: CUBA. Pinar del Río: Herradura. 1905. Van Hermann 779 ♀ (HAC!, HAJB!, B?). There is a mysterious specimen at B (B_10_0247709) labeled R. cephalocarpa and annotated by Knuth as “Typus”. There is no date, collector name or number on the label, only the locality “Cuba”. It may be one of the Van Hermann collections but I have not been able to confirm this

Rajania hermannii Knuth (1917: 222) . Type:— CUBA. Pinar del Rio: Herradura, 1903, Van Hermann 740 ♂ (holotype B!).

Dioscorea rigida Knuth (1925: 79) . Type:— CUBA. Pinardel Rio: Sierra del Sitio Santo Tomas, Ensenada de Vega Cuchilla, ca. 500 m, 12 June 1923, E. L. Ekman 16681 ♂ (holotype S!, isotypes B! [2 sheets: B100247707, B100247708]).

Notes: Endemic to Pinar del Rio, Cuba. Although a Van Hermann 779 duplicate has been located at HAC with the clustered fruits typical of this species, it has somewhat anomalous leaf venation and therefore does not best represent D. cephalocarpa . The Wright 1712 collection, complicated as it is, better represents the typical morphology of this species. Much of the taxonomic confusion in Rajania can be traced to Wright 1712. This collection includes a total of six species mixed in different combinations of up to four species per sheet in at least 31 sheets (9 at HAC alone), dispersed across 12 herbaria (B, BM, BREM, F, GH, HAC, K, MO, NY, S, US, YU). There is also almost certainly a sheet at GOET, where Grisebach was based while he compiled his Cuban catalogue of Wright’s material, but I haven’t seen it. In all, there may be as many as 40 “duplicates” (see Howard (1988) for a history of the handling of Charles Wright specimens), each with a unique combination of elements. Nearly all the specimens I’ve seen are annotated simply as “ R. hastata ” by Wright himself, but the full species composition of this collection number includes what are here called: D. cephalocarpa , D. confusa , D. introrsa , D. psilostachya D. scorpioidea , and D. theresensis .

“Wright 1712 pro parte” is cited among the syntypes of both R. cephalocarpa and R. wrightii , but Knuth never made clear which part(s) of which duplicate(s) he was referring to, and the descriptions (1917, 1924) reflect the mixed nature of the collections. As a result of this ambiguity, interpretation of all the above species has been confused, and the name R. hastata has been misapplied (also see discussion under D. bahamensis and D. alainii ).

Rajania cephalocarpa was described primarily from pistillate material (Knuth did not see the majority of the staminate isolectotypes cited here). Staminate plants of this species were described unambiguously, years later, under the name Dioscorea rigida ( Knuth, 1925) .

Not included in the list of synonyms is “ R. wrightii var. cephalocarpa Uline ”, an annotation by Uline on Wright 1712 p.p. (GH “2C”, my designation). The combination was never published, nor was it cited by Knuth as “in msc”.