1953] 



BOTANY OF THE GUAYANA HIGHLAND 



103 



Very shortly caulescent herb; stems 0.5*2 cm„ long, or perhaps longer, 

 rooting near the apex, often branched and leaf-bearing there, the leaf-bearing 

 portion usually about 5 mm. long; leaves linear, 1-2 cm. long, about 0.5 mm. 

 wide, spreading, biunnescent in age, blunt at the apex, glabrous, rather firm- 

 textured, not plainly venose; sheaths very slender, closely appressed, 1-1.5 cm. 

 long, not plainly striate nor twisted, glabrous, obliquely split at the apex, the 

 blade oblong, about 3 mm. long, erect, blunt at apex; peduncles 1 or 2 per branch, 

 very slender, stramineous, 3.5-9.5 cm. long, 3-costate, more or less white-pilose 

 toward the base, glabrescent toward the apex; heads hemispheric, white, 3-6 mm. 

 wide; involucral bractlets in several series, the outermost smallest, the innermost 

 largest, stramineous, elliptic-obovate or the outermost ovate, 1.6-2.4 mm. long, 

 1-L5 mm. wide, rounded and usually emarginate-split at the apex, the outermost 

 often more or less laciniate, glabrous, shiny; receptacle densely long-pilose; 

 receptacular bractlets oblong, whitish, about L5 mm. long and o 5 mm. wide, ob- 

 tuse at the apex, very densely long-barbell ate with white hairs on the back at the 

 apex, otherwise glabrous; staminate florets: sepals 3, separate, stramineous, 

 spatulate, about 1,5 mm. long and o 5 mm. wide, rounded and rather densely 

 barbellate at the apex, otherwise glabrous; petals 3» connate into a stramineous 

 infundibular tube about L5 mm. long, glabrous; stamens 3; pistillate florets: 

 sepals 3, pale-stramineous, oblong, about 2.2 mm. long and OA mm. wide, sparsely 

 short-pilose at the apex on the back, otherwise glabrous; petals 3, subhyaline, 

 lanceolate, about 2 mm. long, attenuate at the apex, sparsely short-pilose at the 

 apex, otherwise glabrous; style about 1 mm. long, glabrous; stigmas 3, about 0.5 

 mm. long;, ovary stramineous, subglobose, about 0.8 mm. long and wide, 3-sulcate, 

 3-celled, 3-ovulate. 



TYPE: locally frequent in wet savanna No. I, 125 m. alt., Cerro Yapacana, 

 Rio Orinoco, /mazonas, Venezuela, January 7, 1951, S. Maguire, R. S. Cowan & 

 J. J. W'urdack 30782; New York Botanical Garden. 



L EGUMINOSAE-C AESALPINIOIDEAE 



In attempting to identify the collections of the genus Aldina it was at once 

 apparent that one of the collections was most certainly a new species and further 

 study revealed that the other three represented material of a second undescribed 

 species, ^ith the exception of two new species described by Ducke nothing has 

 been added to our understanding of this interesting genus since the treatment in 

 the Flora brasiliensis; here no key was presented and the descriptions were often 

 incomplete and inadequate. Because of this situation, I have undertaken a prelim- 

 inary review of the genus. 



The material on which this review is based is admittedly scanty and for this 

 reason it is to be considered only as a preliminary study. It was a fortunate cir- 

 cumstance to have in our herbarium the holotypes or isotypes of all but one of 

 the described species and this one was kindly loaned by the U. S. National Her- 

 barium; for this assistance I am indeed grateful. 



Key to the Species and Varieties of Aldina 



1. Leaflets completely glabrous on lower surface as well as the upper 2 



1. Leaflets pubescent on lower surface, sometimes obviously but often minutely so. . 3 



2. Mature buds 7-8 mm. long, petals 7-9 mm. long; stipe of ovary as long as or shorter 



than ovary; leaflets broadly ovate to lanceolate; inflorescence much-branched. 



10. A. heterophylla. 



2. (Mature buds . 15 mm. long, petals 15-20 mm. long; stipe of ovary 2-3 times as long as 

 ovary; leaflets oblong, oblong-oval, or oblong-ovate; inflorescence racemose or lax 

 and sparsely branched 4a. A. latifolia var. latifolia. 



