THE BOTANY OF THE GUAYANA HIGHLAND— PART II 



339 



I. Section Dicymbe. 



A sectione Triplopetala petalis 5, sessilibus differt. 



1. Dicymbe heteroxylon Ducke, Trop. Woods 81:6. 1945. 



This large forest tree is readily recognized by its small, lanceolate leaflets, 

 its smaller flowers in which the hypanthium is shallowly cupular. The inequal 

 androecium clearly relates it to D. altsoni; the leaflet pubescence also is iden- 

 tical in the two species. 



Only one sheet, on which parts of both the flowering and the fruiting collec- 

 tions originally cited are attached, has been seen. 



2. Dicymbe altsoni Sandwith, Kew Bull. 1928:371. 1928. 



Trees of this species 20-35 m tall and 30-60 cm in diameter have been 

 measured. It is in some sections of British Guiana very common, if not the 

 dominant tree. 



The size of the flower parts is variable, the petals especially; the one large 

 petal varies from 2.5 to 3.5 cm in diameter and the other four from 1.5 to 2.2 cm 

 in width. The filaments in the type collection vary from 7-17 mm in length while 

 in a later collection they range from 15 to 25 mm long. The cupular hypanthium, 

 free bracteoles, and inequal androecium relate this species to D. heteroxylon; the 

 latter has narrowly lanceolate leaflets and smaller flowers. 



The fruit was not known at the time of the original description but now a 

 specimen with fruit has been collected. It is sericeous, alate at the dorsal 

 margin, oblong, about 14 cm long and 4 cm wide. The seeds are compressed, oval 

 in outline, 28-33 mm long, 24-26 mm wide. 



Besides the type collection, Altson 459, the following collections represent this 

 species: BRITISH GUIANA: Bartica-Potaro Road, Fanshawe 1057 (F. D. No. 3793), 2702 

 (F. D. No. 5495), 2749){¥. D. No. 5548). 



3. Dicymbe corymbosa Spruce ex Benth. Trans. Linn. Soc. 25:30 3- 1865. 



A complete description of this species is needed but until all the extant 

 collections are assembled, it would seem to be unwarranted. An isotype and three 

 other collections are at hand; only those parts not described originally in full are 

 treated below. 



Petioles 12-20 mm long, leaflets glandular-punctate and coarsely reticulate- 

 veined on the lower surface, nitid above and with the costa salient and the veins 

 plane. Inflorescence velutinous, bracts concave, oblong-oval, 10 mm long, 8 mm 

 wide, obtuse, densely strigulose on outer surface, glabrous within except 0.5 mm 

 wide tomeatulose marginal band. Bracteoles ovate, deeply concave, fin bud) 18 

 mm long, 10 mm wide, thick-coriaceous, densely strigulose on the outer surfaces, 

 glabrous within. Hypanthium shallowly cupular, 3 mm deep, 5 mm in diameter, 

 densely strigulose outside, glabrous within; sepals ovate, cucullate apically and 

 minutely erose marginally, glabrous, (in bud) 13 rnm long, 7-8 mm wide; petals 5, 

 elliptic, acute, glabrous except for broad sericeous band on the back of each; 

 filaments 7.5-11 mm long (in bud), villose in the basal half, anthers 9-10.5 mm 

 long with the connective villose; stigma peltate, 0.7 mm in diameter; style 

 glabrous; ovary oblong, sericeous, 8 mm long, 2 mm wide, nearly sessile. Fruit 

 oblong, 25 cm long, 4 cm wide, sulcate and bi-alate on dorsal margin, sparsely 

 strigose and minutely gland-dotted, about 5-seeded. 



Collections representing this species are: BRITISH GUIANA: Fanshawe 1017 (F. D. 

 No. 3753), Fanshawe 2716 (F. D. No. 5515), Lang 312. BRAZIL: Spruce 2791 (type 

 collection number). 



The disjunction between the source of most of the collections and that of the 

 type collection might raise legitimate questions, were there much morphological 



