Dioscorea quinquefolia

Raz, Lauren, 2016, Untangling the West Indian Dioscoreaceae: New combinations, lectotypification and synonymy, Phytotaxa 258 (1), pp. 26-48 : 37-39

14. Dioscorea quinquefolia (L.) Raz, comb. nov. Rajania quinquefolia Linnaeus (1753: 1032) . Lectotype (designated here):— DOMINICAN REPUBLIC (“Hispaniola”). Plate 493 of the Boerhaave set of Plumier illustrations at the library of Rijksuniversiteit, Groningen (used to create the composite drawing in Tab. 155 of Plumier 1758; Fig. 2 )

Rajania mucronata Willdenow (1806: 787) . Type:— HAITI. “Domingo”, no date, Poiteau s.n. ♂ ♀ (holotype B). I have not examined the specimen in person, just a black and white microfiche photo in the library at NY, supplemented by Kunth’s (1850, p. 447) exquisitely detailed description of the type.

Rajania quinquenervia Rafinesque (1840: 125) . Lectotype (designated here):— CUBA. “ Mt. Jalambic ”, no date, E. Durand s.n. (lectotype DWC!).

Rajania cubensis Kunth (1850: 446) . Rajania angustifolia Grisebach ex Kunth (1850:446) pro syn. Type:— CUBA. In sylvis petrorsus insulae Cubae, August, 1822. Poeppig s.n. (holotype B!, isotypes K!, MO!).

Dioscorea lanceolata C.Wright ex Grisebach (1866: 251) . Lectotype (designated here):— CUBA. Oriente [Holguin]: Barajagua (note: this locality is likely to refer only to part of the mixed collection), 1860-64, Wright 3253 ♂ (lectotype HAC!, isolectotypes BM “A”! (part B is a fragment of D. alainii , collected by Reading in “Ste. Dominique” in 1803), GH “B”! (part A is D. haitensis ), MO!, S!).

Rajania wilsoniana Morton (1933: 85) . Type:— CUBA. Santa Clara (Cienfuegos): Limones , Soledad , July 18, 1929, J. G. Jack 7489 (holotype: NY; isotypes GH, HAC).

Rajania angustifolia auct. non Swartz in Knuth (1924: 324) and León (1946: 323).

Notes: Cuba and Hispañola. Although it is one of the earliest names in Rajania , R. quinquefolia fell out of use shortly after its publication. The type ( Fig. 2 ) is a schematic illustration of the leaves and fruits, but it can nevertheless be unambiguously interpreted, as there are no other Rajania species with both fasciculate leaves and acutely angled secondary venation. Knuth (1924) never cited the illustration and included the name in a list of unplaced and uncertain taxa at the end of his treatment. Liogier (1969) resurrected R. quinquefolia and listed R. mucronata as a synonym. He did not however comment upon the existence of narrow and wide leaved forms of this species.

The plate selected here as the lectotype appears in a modified form in Plumier (1758: Tab. 155 Fig. 2 ). The latter version is truncated, with only a single node, while Plate 493, reproduced here in Fig. 2 , has two nodes. In Tab. 155 Fig. 2 , a staminate inflorescence was also added (a highly schematic drawing that is essentially the same as the staminate inflorescence drawn for R. cordata ), but since all Sect. Rajania species are strictly dioceous, it is inaccurate to represent them as monoecious. I would like to note that Tab. 155 Fig. 1 of Plumier (1758) also includes flowers and a detached fruit that were copied directly from a different Plumier source (1703: Tab. 29). In the latter work these drawings are used to represent the genus Ian-raia, and not any particular species; it is therefore inappropriate to depict them as specifically representing R. cordata , as Burman had done in his edition of Plumier (1758). The samara depicted in Tab. 29 of Plumier (1703) is slightly more stylized than that represented in plates 491 and 493 of the Codex Boerhavianus, but it is this more stylized version that was later incorporated into the drawings of the infructescences depicted in Tab. 155 (1758). Together with the above mentioned plates, in the library of the University of Groningen, there is also a proof sheet of the complete Tab. 155, plus a second, less complete version of the R. quinquefolia drawing. The proof sheet was almost certainly seen by Linnaeus, and while I cannot, with the same degree of certainty, assert that Linnaeus saw Plates 491 and 493 of the Codex Boerhavianus, being the original elements upon which Tab. 155 was based, these are preferred for lectotypification.

The use of R. angustifolia Sw. for this taxon dates to Knuth (1924) who cited primarily Cuban material as the basis for his description. It appears he did not examine the Swartz type, which differs markedly in leaf venation, floral and inflorescence morphology, and is restricted to Hispaniola (see Dioscorea microflora above).

Leaf width of Dioscorea quinquefolia varies across a continuous spectrum, but all forms are identical in their floral morphology. Narrow-leaved specimens from Cuba (associated with serpentine formations) and Hispañola have traditionally been interpreted as “ R. angustifolia ”, while specimens with leaves of intermediate width from Cuba and Hispañola have been called R. mucronata , and broad-leaved specimens from Cienfuegos, Cuba have been treated as R. wilsoniana . The latter are restricted to karst formations in and around what is today the Jardin Botanico de Cienfuegos (formerly the site of the Atkins Biological Station of Harvard University). At this locality the leaves are ovate, thin, membranaceous with conspicuous raphids, and an indumentum of fine white hairs, abaxially. Morton (1933) believed it to be more closely related to R. pilifera , but the flowers don’t accord. Morphological and molecular studies by Raz (2007) place it squarely within D. quinquefolia .

In Hispaniola D. quinquefolia appears to be introgressing with D. alainii .

Figures

FIGURE 1. Lectotype of Rajania cordata L.—Plate 491 of the “Codex Boerhaavianus”. It is a copy, made for Boerhaave, of a Plumier drawing representing Janraja scandens folius tamni (Plumier 1703: 33), a verion of which appeared subsequently in Plumier (1758: Tab. 155 Fig. 1) as “Raja foliis simplicibis, cordatus”. Courtesy of the library of Rijksuniversiteit, Groningen.

FIGURE 2. Lectotype of Rajania quinquefolia L.—Plate 493 of the “Codex Boerhaavianus”. It is a copy, made for Boerhaave, of a Plumier drawing representing Janraja scandens quinquefolia (Plumier 1703: 33), a version of which appeared subsequently in Plumier (1758: Tab. 155 Fig. 2) as “Raja foliis quinis”. Courtesy of the library of Rijksuniversiteit, Groningen.