Mascagnia dissimilis C.V.Morton & Moldenke

Authority

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

Family

Malpighiaceae

Scientific Name

Mascagnia dissimilis C.V.Morton & Moldenke

Description

Species Description - Woody vines, the stems glabrous or glabrate, older stems up to 1 cm in diameter. Lamina of the larger leaves 14-25 cm long, 6.5-11 cm wide, ovate or oblong, obtuse or rounded at the base, smooth and slightly revolute at the margin with a discolored band 0.5-1 mm wide, abruptly acuminate at the apex with the acumen 10-15 mm long, initially sericeous but very soon glabrate, eglandular or bearing up to 4 impressed glands at the base below and up to 6 distally, the reticulum raised or obscure on both sides; petiole 11-18 mm long, glabrous, eglandular; stipules ca 1 mm long, triangular, interpetiolar. Inflorescence axillary, minutely velutinous, an open panicle of 5-8 elongated to subcorymbose pseudoracemes 2-10 cm long, composed of (4-)7-40 flowers each; bracts 0.7-1 mm long, eglandular; peduncle (2-)3-5(-8) mm long; bracteoles ca 0.5 mm long, eglandular or abaxially somewhat callose, borne between the middle and the apex of the peduncle or at the apex. Pedicel 11-14(-23) mm long, glabrous. Sepals exceeding the glands by 0.7-1.5 mm , obtuse or rounded at the apex, entire or denticulate, glabrous on both sides, the lateral 4 biglandular with the glands 2-3 mm long, the anterior sepal eglandular. Petals white, glabrous, the outermost exposed in the enlarging bud, with the limb ca 5 mm long, 3-3.5 mm wide, obovate, minutely denticulate, membranous, abaxially carinate, the winged claw ca 1 mm long. Filaments 1.5-3 mm long, glabrous, flanged and connate at the base, distally slender except opposite the posterior-lateral petals, those 2 filaments thick and broad; anthers 1.5-1.7 mm long, glabrous. Ovary sparsely sericeous; styles ca 2.5 mm long, the anterior slightly longer than the posterior 2, glabrous, laterally flattened, dorsally truncate or with a very short hook at the apex. Samara (2-)2.5-3.6 cm high, (2-)2.5-3.2(-4.3) cm wide, ovate or orbicular, glabrate at maturity or with a few hairs on the nut, the lateral wing membranous, continuous at base and apex, emarginate at the apex, entire or slightly sinuate; nut eccentric; central dorsal winglet 2-6 mm wide; intermediate winglets none; ventral areole ovate, about 3 mm long and 2 mm wide.

Discussion

Type. Lawrance 546, El Umbo, Boyaca, Colombia, 21 Oct 1932 frt (holotype NY! isotype A!). This species is similar to Mascagnia nervosa Niedenzu, from which Cuatrecasas (1958) distinguishes it by the lack of a prominent reticulum on the upper side ofthe leaves in M. dissimilis. That characteristic is not very consistent, and the separation is better achieved on the basis of the larger ovate or oblong leaves of M. dissimilis with a distinctive discolored band at the margin. M. nervosa seems to be a species of NW Venezuela and adjacent Colombia and Panama. A possible synonym for M. dissimilis is Mascagnia filipes Macbride, described in 1950 in the Flora of Peru with Klug 815 from Mishuyacu near Iquitos as type; I have not seen that coHection.

Distribution

Distribution. Western Amazonia. VENEZUELA. Amazonas: Tamatama, edge of Orinoco, elev 121 m. May frt, LI. Williams 15107 (F, US, VEN). BRAZIL. Amazonas: Rio Papury, Vaupes, Rio Negro, Oct frt, Froes 21200 (IAN, NY, US). COLOMBIA. Antioquia: Tirana Creek, at confluence with Río Anori, Mpio Anori, Apr frt, Soejarto et al 3928 (NY). Boyaca: type, qv. Caqueta: 10 km S of San Jose de Fragua, elev 320 m, Jan bud. Gentry et al 9141 (MICH). PERU. Loreto: Prov. Maynas, Puerto Almendra, Feb flr/frt, Revil

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