Deguelia rufescens (Benth.) R.A. Camargo & A.M.G. Azevedo, 2018

Camargo, Rodrigo A. & Tozzi, Ana Maria G. A., 2018, New Combinations in Deguelia (Leguminosae, Papilionioideae) for the Guiana Shield, Phytotaxa 356 (4), pp. 285-290 : 288

Deguelia rufescens (Benth.) R.A. Camargo & A.M.G. Azevedo , comb. nov.

Basionym:— Lonchocarpus rufescens Benth. (1839: 432) . Derris rufescens (Benth.) Ducke (1949: 197) . Lectotype (designated here):—

GUIANA. Pirara , 1838, R. Schomburgk 745 ( K000117572 !; isolectotypes: BM!, C!, F!, K000478108 !, L!, P!). = Lonchocarpus nitidulus var. schomburgkii Benth. (1860: 98) . syn. nov. Lectotype (designated here):— GUIANA. Roraima. 1842–3, Rob. Schomburgk 733 & Rich. Schomburgk 1111 ( K!; isolectotypes: BM!,

NY [digital image!], P! [digital image!]).

This species is similar to Deguelia urucu , sharing a similar calyx and also the presence of trichomes on the inner face of the petals (sparsely distributed towards the apex), but it can be readily distinguished by its narrower leaflets that bear ferrugineus trichomes underneath it (as opposed to brownish), by its inflorescence size (always twice as long as the leaf, as opposed to subequal or smaller), and by the morphology of its keel petals (elliptical with a truncate base, as opposed to oblong with an auriculate base). The collection Rob. Schomburgk 733 & Rich. Schomburgk 1111 was used to describe Lonchocarpus nitidulus var. schomburgkii Bentham (1860: 98) . However, this variety shares exclusive characters with D. rufescens that are not present in Deguelia nitidula (Benth.) A.M.G. Azevedo & R.A. Camargo (2014: 16) and should not be considered a variety of the latter as proposed by Bentham (1860: 98). D. nitidula presents many distinctive morphological characters, such as smaller, wider leaflets with a particular indumentum underneath (short and adpressed trichomes as opposed to tomentose), calyx with subequal carenal teeths (all with similar width) and petals glabrous on the inner face. Although only the type collections were examined, both share the same combination of diagnostic features, and therefore a new synonym is proposed here.

Distribution and habitat: —Occurs only in Guiana. Very few specimens have been collected for this species, thus more collections are needed to clarify its distribution and ecological preferences. Although Lonchocarpus rufescens Benth. and some vernacular names are cited by DeFilipps et al. (2004) for its use as a fish poison in the Maroni region of the French Guiana, these data were disregarded. This name was possibly incorrectly applied due to a misidentification issue from the compiled literature used by these authors, who also did not presented vouchers. Additionally, we could not find any material from this species for French Guiana. Herein, this species is considered endemic to Guiana.