1958] 



THE BOTANY OF THE GUAYANA HIGHLAND PART III 



153 



Pterocarpus amazonum (Mart, ex Benth.) Amshoff. 



VENEZUELA: Amazonas: "ArbolTm. Flores amarillas. " Rio Orinoco between mouth 

 of Eio Atabapo and Cafio Masagua 10 km upstream, elev. 150 m, May 16, 1954, J. S. Level 94., 



This is the first record of this distinctive species in Venezuela ; it was known 

 previously from Amazonian Brazil, Colombia, Peru, and Ecuador. The species is 

 characterized by swollen inflorescence-axes which serve as formicaria; it was 

 formerly better-known as P. ulei Harms, but this is clearly a later name for the 

 Bentham species, as Amshoff has shown. 



Stylosanthes angustifolia Vogel. 



VENEZUELA: Bolivar: flowers yellow. Locally frequent at base of Cerro San Borja, 

 Eio Orinoco, elev. 100 m, WurdacTc 4' Monachino 39850. 



This is a very infrequent species in Venezuela and until very recently it was 

 unknown in the country. It is quite distinct by virtue of its narrowly cylindrir 

 inflorescences and uniflorous bracts. It has been recorded previously from Brazil 

 and the Guianas. 



RUTACEAE 27 



Decagonocarpus oppositifolius Spruce ex Engler. 



VENEZUELA: Amazonas: frequent on granitic summit of Piedra Nunca (just north of 

 Piedra Cucuy), elev. 200-250 m, Eio Negro, Apr 1953, Maguire ^ Wurdack 34952; frequent 

 on open lower and middle slopes of Piedra Arauicaua, elev. 120-170 m, rios Pacimoni-Yatua, 

 Feb 1954, Maguire, Wurdack $ Bunting 37475 ; frequent in open areas on Piedra Tururumeri, 

 rios Pacimoni-Yatua, Casiquiare, elev. 110-220 m, Feb 1954, Maguire, Wurdack 4° Bunting 

 37493. 



Until Maguire et al. made several collections of this species, this monotypic 

 genus was known in Venezuela only by the type collection. In the first install- 

 ment of the 1 'Botany of the Guyana Highland" these collections were reported 

 and observations concerning the morphology and ecology of the species were 

 recorded there. 



The collections cited above, from the type region, add little to our knowledge 

 of the species morphologically. It is interesting to note that in all three collec- 

 tions, the corollas and the under sides of the leaves are sparsely to distinctly 

 pubescent, as described originally, while the collections from farther north are 

 glabrous ; there do not appear to be any other differences. 



Decagonocarpus cornutus Cowan, sp. nov. Figure 18. 



Arbuscula 1-2 m alta, ramulis glabris vel puberulis, nitidis ; petioli glabri, 

 teretes, (3-) 4—8 (-10) mm longi ; foliorum laminae glanduloso-punctatae, 

 crassae, carnosae, ellipticae vel oblanceolato-ellipticae, glabrae, apice obtusae 

 usque ad rotundatae, basi cuneato-acutae, margine anguste valde revolutae, (25-) 

 30-60 (-70) mm longae, (12-) 15-30 mm latae, supra eveniae, infra costa promi- 

 nenti, venis subobscuris; inflorescentiae unilateraliter racemosae, axe leviter pu- 

 berulo, pedunculo 9-16 mm longo, rhache ca. 7-58 mm longa, pedicellis 4-5 mm 

 longis; calyx brevi-cupulatus, 2.5-4 (-5) mm longus, glaber (vel in var. sparse 

 puberulus et ciliolatus), lobis 1-1.5 mm longis, triangularibus (vel suborbicu- 

 laribus in var ; corolla carnosa, aurantiaco-rubra, tubo 23-28 mm longo, externe 

 glabro (vel in var. plerumque puberulo), intus villoso, apicem versus gradatim 



27 By Richard S. Cowan. 



