Diplopterys

  • Authority

    Gates, Bronwen. 1982. Banisteriopsis, Diplopterys (Malpighiaceae). Fl. Neotrop. Monogr. 30: 1-238. (Published by NYBG Press)

  • Family

    Malpighiaceae

  • Scientific Name

    Diplopterys

  • Type

    Type species. Diplopterys pauciflora (G. F. W. Meyer) Niedenzu.

  • Description

    Genus Description - Lianas, stipules interpetiolar, small to minute. Leaves simple, opposite, the petiole appressed-sericeous, eglandular or apically Eglandular, the lamina entire, bearing numerous minute glands along the margin, the gland on each side of the midrib nearest the base often enlarged, acuminate to long-acuminate at the apex, adaxially glabrous, abaxially sparsely appressed-sericeous. Inflorescence axillary, of 4-flowered umbels, borne singly or in racemes of up to 7 umbels. Bracts and bracteoles eglandular, lingulate, spreading, persistent, appressed-sericeous abaxially, glabrous adaxially. Pedicels sessile, appressed-sericeous. Flowers hermaphroditic. Calyx of 5 sepals, usually the anterior sepal eglandular, rarely 1-glandular, the 4 lateral sepals Eglandular abaxially. Petals 5, yellow, clawed, the limb orbicular to broadly elliptic, externally sparsely sericeous in the middle, long-fimbriate, eglandular, the posterior petal with the claw longer and thicker, the limb obovate. Stamens 10, all fertile, the filaments glabrous, those opposite the sepals longer than those opposite the petals, those of the 3 posterior stamens inflexed between the posterior styles, anthers with the locules sparsely hairy or glabrous, the margin of the pollen sacs along the line of dehiscence membranaceous, the connectives papillose, those opposite the sepals larger than those opposite the petals. Gynoecium of 3 carpels, each uniovulate, free, adnate to a pyramidal torus, densely hairy, embryo adaxial, pendent, anatropous. Styles 3, free, hairy at the base or for up to half their length, stigmas capitate. Fruit of 3 mericarps without carpophore, sometimes only 1 or 2 developing. Nut of the mericarp with hard woody pericarp, bearing a dorsal crest and 2 to several lateral winglets or crests parallel to the areole and interconnected by ridges, appressed-sericeous. Locule of the mericarp more or less spherical, quite smooth.

  • Discussion

    The genus Diplopterys was first described by Adrien de Jussieu for the single species D. paralias, which is a synonym for D. pauciflora. The genus has traditionally been allied with the mascagnioid genera because of its fruit without a dorsal wing and with well-developed lateral winglets, and Niedenzu included the mascagniolid genera Jubelina and Mezia in Diplopterys. However, the flowers of Diplopterys are very similar to those of Banisteriopsis, and specimens of Diplopterys in flower are often misidentified as Banisteriopsis. Species of Diplopterys closely resemble species within the subgenus Pleiopterys section Anisopterys of Banisteriopsis in the marginal glands on the lamina, sericeous petals, and the form of the androecium and gynoecium. The lingulate, spreading bracts and bracteoles of Diplopterys distinguish specimens of this genus from all but two species in section Anisopterys; the long-fimbriate, sparsely sericeous petals of Diplopterys distinguish it from these two species, Banisteriopsis patula and B. krukoffii, which have dentate to lacerate, densely sericeous petals.

    In fruit, Diplopterys appears very distinct from Banisteriopsis with its absence of a dorsal wing, but the reduction of the dorsal wing to a dorsal crest is found in three species within Banisteriopsis, B. cipoensis, B. paraguariensis and B. sepium; if the fruit of Diplopterys is regarded as a banisterioid fruit with well-developed lateral winglets and the dorsal wing reduced to a crest, the derivation of Diplopterys from a banisterioid ancestor is readily postulated.

    The four species of Diplopterys form a cohesive group with the members of the group more similar to each other than to any Banisteriopsis species. I have chosen to maintain this small group as a separate genus because of the unusual nature of the fruits; I feel that inclusion of Diplopterys within Banisteriopsis would distort the definition of the genus unnecessarily. The interconnection of the lateral winglets by ridges to give a more or less reticulate surface to the nut is not found within Banisteriopsis. Perhaps this reticulation traps air to provide buoyancy and the fruits are water-dispersed; the natural habitat of Diplopterys appears to be riverine. Large nut size and reduction of the dorsal wing to a crest are represented in Banisteriopsis. Large nut size is usually found in species in which the whole samara, including the dorsal wing, is greatly enlarged; only in B. sepium is the nut enlargement associated with a reduction of the dorsal wing. But this species and the two other species of Banisteriopsis with reduced fruit wings are each very similar to one or more other species within the genus with well developed fruit wings, and differ principally from these species in the degree of development of the fruit wing; the three species in Banisteriopsis with the dorsal wing reduced to a crest are not at all similar to each other in other respects.

  • Distribution

    Two of the four species are Amazonian in distribution, one species occurs in northeastern South America (Para, French Guiana) and the remaining species is from Veracruz in Mexico.

    Mexico North America| French Guiana South America| Brazil South America| Peru South America| Colombia South America| Venezuela South America| Ecuador South America| Bolivia South America| Guyana South America| Suriname South America|