Monographs Details: Distictella laevis (Sandwith) A.H.Gentry
Authority: Maguire, Bassett. 1978. The botany of the Guayana Highland--part X. Mem. New York Bot. Gard. 29: 1-288.
Family:Bignoniaceae
Discussion:7. Distictella laevis (Sandwith) A. Gentry, comb et stat nov Distictella monophylla var laevis Sandw., Mem. N. Y. Bot. Gard. 9: 362. 1957. Type. Venezuela: Amazonas, Bassett Maguire et al 30788 (NY). Sandwith had seen only two rather poor specimens of this taxon when he described it as a variety of D. monophylla, the only other simple-leaved Distictella. Several additional specimens have subsequently been cohected. ''Laevis'' turns out to have a much wider range than previously suspected, also occurring south of the Amazon in the upper Tapajos area of Para, Brazil (Anderson et al 10539 (MO), 19028 (MO), 10783 (NY), 10684 (NY), Egler 1187 (INPA)) and in Rondonia [Prance et al 5832 (INPA, NY)]. The smooth glabrous leaf undersurface with immersed venation which distinguishes laevis from intricately raised reticulate and puberulous var monophylla proves constant in ah these cohections. I consider the striking difference in leaf surface sufficient to justify specific segregation. Distictella laevis is thus a widespread lowland (below 400 m) species with a trans-Amazonian distribution while D. monophylla, restricted to Amazonas, Venezuela and adjacent Colombia, ranges altitudinally from 140 m to 1600 m. In addition to the vegetative differences noted by Sandwith, D. laevis has an inflorescence with more flowers and a longer (1 mm vs 0.5 mm) stipe below the ovary. The only fruiting collection I have seen of D. laevis has capsule valves splitdng down the midline; if constant, this also disdnguishes D. laevis from D. monophylla which has non-splitting valves.