Mascagnia microcarpa (Sandwith) W.R.Anderson

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 microcarpa (Sandwith) W.R.Anderson

Description

Species Description - Woody vines, the stems sericeous, soon glabrate. Lamina of the larger leaves 9-13(-16) cm long, 4-7(-8) cm wide, ovate or elliptical, cuneate or rounded at the base, revolute at the margin, acuminate at the apex, very sparsely sericeous to nearly or quite glabrate on both sides, bearing many tiny impressed glands on the adaxial surface of the revolute margin; petiole 8-13 mm long, sericeous to glabrate, eglandular or bearing 2(-4) small glands on the distal half; stipules 0.3-0.5 mm long, triangular, interpetiolar. Inflorescences axillary congested panicles shorter than (usually less than half the length of) the subtending leaf, sericeous throughout to glabrate, the flowers mostly borne in corymbose clusters of 4-8 or more; bracts 1.5-3 mm long, ovate or triangular, appressed, eglandular; peduncle 1-3 mm long; bracteoles 1-1.5 mm long, ovate or triangular, appressed, eglandular, borne at the apex of the peduncle. Pedicel 5-20 mm long, sericeous to glabrate. Sepals leaving the outer petal exposed during enlargement of the bud, ca 3 mm long and 2 mm wide, appressed after anthesis, broadly rounded at the apex, abaxially densely sericeous except the margin, adaxially glabrous, the lateral 4 biglandular with the glands 2.5-3 mm long, free at the apex, the anterior sepal eglandular. Petals yellow, very densely golden-sericeous abaxially on claw and limb except margin, the lateral 4 reflexed, with the claw ca 2.5 mm long and the limb 5-7 mm long, 4-6 mm wide, concave, denticulate or erose, the posterior ± erect, with the claw 2-3 mm long and the limb 3-5 mm long, 2-3 mm wide, flat or crumpled, glandular-fimbriate ± all around the margin. Filaments 2.5-3 mm long, abaxially proximally sericeous, adaxially sparsely sericeous, straight, 1/3-1/2 connate; anthers 1.3-1.8 mm long, those opposite the sepals longer (with more pendent locules) than those opposite the petals, glabrous or sparsely sericeous abaxially on the connective. Ovary 1-1.5 mm high, sericeous; styles 2.5-3 mm long, equal, glabrous except at base, straight and divergent, dorsaHy rounded or truncate or very short-apiculate at the apex, with broad internal stigmas. Samara with the nut 5-8 mm in diameter and the wings small and thickened, coriaceous or aerenchymatous, the 2 lateral wings discrete, 5-9 mm wide, coarsely and irregularly toothed, the central dorsal wing 1-3 mm wide or reduced to a rounded ridge, entire; intermediate winglets none; ventral areole elliptical, 5-7 mm long, 2.5-4 mm wide.

Discussion

9. Mascagnia microcarpa (Sandwith) Anderson, comb nov Diplopterys microcarpa Sandwith, Kew Bull, 1931: 183. 1931. Type. Sandwith 289, Morabaili Creek, near Bartica, Essequibo River, British Guiana [Guyana], 18 Sep 1929 (holotype K , isotype NY!). This is a lowland species that is included here only because the Mazaruni coHections cited above place it within the flora of Guayana as defined in this paper. This species is quite unlike other species of Mascagnia in Guayana. It is very closely related to M. sinemariensis (Aublet) Grisebach, from which it differs only in the samara, which has an enlarged nut and reduced, corky wings in M. microcarpa.

Distribution

Distribution. Guayana collections: GUYANA. Mazaruni River: long. 60°10'W, De La Cruz 2269 (NY), 2361 (F, GH, MO, NY), & 2399 (F, GH, MO, NY); Kamakusa, long, ca 59°50'W, De La Cruz 2892 (F, GH, MO, NY); Jenman 5370 (NY).

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