Burdachia prismatocarpa A.Juss. var. prismatocarpa

Authority

Maguire, Bassett. 1978. The botany of the Guayana Highland--part XI. Mem. New York Bot. Gard. 32: 1-391.

Family

Malpighiaceae

Scientific Name

Burdachia prismatocarpa A.Juss. var. prismatocarpa

Description

Variety Description - Shrubs or trees 2-15 m tall, the vegetative stems sericeous to glabrate. Lamina ofthe larger leaves 11-21 cm long, 6-12(-14) cm wide, ovate or elliptical, mostly rounded or cordate at the base, flat or slightly revolute at the margin, mostly obtuse or rounded at the apex, often emarginate and then sometimes apiculate, glabrate above, sparsely but ± persistently sericeous below, the hairs short, fine, sessile, bearing 2 large glands below at the base on the midrib and few to many tiny impressed glands distally scattered or concentrated along the midrib, the lateral veins strongly parallel and prominent below, the reticulum prominulous on both sides; petiole 10-25 mm long, thick, sericeous to glabrescent, eglandular; stipule-pair 6-10 mm long, ovate or triangular, acuminate to broadly rounded at the apex, concave to flat or slightly revolute and often thin at the margin, abaxially sericeous to glabrate, adaxially densely orange-hirsute in the proximal half, hirsute or glabrous distally. Inflorescence tomentose-sericeous, each cincinnus of 1-2 (-3) flowers, the bract and bracteoles 1-3 mm long, ovate, membranous at the margin, glabrous or sparsely sericeous, the bracteoles usually borne near the base of the peduncle; peduncle of the cincinnus often sericeous, especially distally. Pedicel 6-10(-12) mm long, glabrous, lengthened and thickened in fruit. Sepals 1.5-2 mm long beyond the glands, 1.5-2 mm wide, broadly obtuse, membranous at the margin, glabrous, the glands pink, 2.5-3 mm long. Petals pink or white, the lateral 4 with the claw 3-4 mm long, the limb 5-7.5 mm long, 5-8 mm wide, orbicular, deeply to shallowly concave, cordate, erose; posterior petal with the claw 2.5-3.5 mm long, the limb 3-4 mm long, 3-4 mm wide, flat or distally reflexed, ovate, bearing large, usually stalked glands at the base and smaller, sessHe glands distally, the glands usually continuous over the apex. Filaments 1.3-2 mm long; anthers 2-3 mm long, variable in the same flower, the connective projecting beyond the locules up to 1 mm, the projection obtuse or rounded, usuaHy reflexed. Ovary conoid, ribbed, ca 1.5 mm high, densely sericeous or tomentose; styles 3-4.5 mm long, sericeous at the base. Fruit 14-20 mm long, 10-18 mm in diameter, pyramidal, bearing 8-9 longitudinal aerenchymatous ribs or winglets (3 per carpel), these usually extended as spurs and often interconnected at the base, rostrate at the apex, green drying brown, tomentose to glabrate, the wall composed of much aerenchyma reinforced by fibers, containing 1 seed (rarely 2).

Discussion

2a. Burdachia prismatocarpa Adr. Jussieu var prismatocarpa Fig 29a-d. Burdachia prismatocarpa war pyramidata Niedenzu, Arb. Bot. Inst. Ak. Braunsberg 5: 60. 1914. Burdachia prismatocarpa var argutivenosa Cuatrecasas, Webbia 13: 636.1958. Type Cuatrecasas 7248, Mitu, Rio Vaupes, Colombia (holotype US! isotypes COL, F! NY!). Type. Martius, Tefe, Brazil (M?). Fruits that seem to be adapted for dispersal by water have evolved in many Malpighiaceae that grow in the Amazon region, but none is more impressive in that respect than the fruit of Burdachia prismatocarpa. Its wall produces a number of ribs or winglets that are composed mostly of aerenchyma, so that the mature fruit is dry, light, and very buoyant. It is worth noting that these ribs are developed in positions that correspond to the lateral and dorsal wings in mascagnioid genera. If the structures are homologous, Burdachia might constitute an intriguing link between the byrsonimoid genera and the wing-fruited genera.

Distribution

Along rivers in Amazonian Brazil and Colombia and middle to upper Orinoco, Venezuela.

Brazil South America| Colombia South America| Venezuela South America|