2953] 



BOTANY OF THE GUAYANA HIGHLAND 



101 



yellow, about 30 per plant, 33-45 cm. long, 3-costate, glabrous, shiny; heads 

 hemispheric, white, 3-6 mm. in diameter; involucral bractlets very tough and firm, 

 concave, closely appressed to the head, yellowish-stramineous, elliptic, about 

 2.5 mm. long and 1 mm. wide, rounded at the apex, glabrous, very shiny; re- 

 ceptacle long-villous; receptacular bractlets whitish-subhyaline, spatulate- 

 obovate, about 2.5 mm. long and 0.6-1 mm. wide, rounded at the apex, appressed- 

 pilose on the entire back; staminate florets: sepals 3, separate almost to the base, 

 spatulate, whitish-subhyaline, about 2 mm. long and 0.5 mm. wide, rounded at the 

 apex, densely barbellate-pilose on the back above the middle; petals 3, connate 

 into a subhyaline infundibular tube about 1.7 mm. long, glabrous; stamens 3; pis- 

 tillate florets: sepals 3, hyaline, narrow-elliptic, about 2 mm. long and 0.5 mm. 

 wide, very shortly barbellate on the back below the apex, otherwise glabrous; 

 petals 3, narrowly oblong-spatulate, about 1.8 mm. long and 0.3 mm. wide, gla- 

 brous; style about 1 mm. long, glabrous; stigmas 3; ovary subglobose, about 1 

 mm. long, 3-sulcate. 



TYPE: in wet places, Savanna No. Ill, 125 rn. alt., Cerro Yapacana, Rio Ori- 

 noco, Amazonas, Venezuela, December 31, 1950, B. Waguire, R. S. Cowan & J. J. 

 Wurdack 30465; New York Botanical Garden. 



Syngonanthus gracilis (Korn.) Ruhl. 



Locally frequent in moist sand among rocks, 15 km. above San Fernando, Rio 

 Atabapo, Rio Orinoco, Waguire 29 267. This is a widespread and extremely vari- 

 able species. The typical form is known from Colombia (Meta and Vaupes), Vene- 

 zuela (Amazonas, Bolivar, and Sucre), British Guiana, and Surinam to Brazil 

 (Amazonas, Minas Geraes, Para, and Piauhy) and Uruguay. No less than 16 poorly 

 defined and poorly understood varieties have been described, chiefly from Brazil. 



Syngonanthus gracilis var. glabriusculus Ruhl. 



With white flowers, in Vellozia association, cumbre at 1200 m. alt., Cerro 

 Yapacana, Rio Orinoco, Waguire, Cowan & Wurdack 30714; freauent on open banks, 

 lower Cano Negro, 4400 feet alt., Rio Cuao, Rio Orinoco, Waguire & Politi 27917. 

 This variety is also known from Bahia and Minas Geraes, Brazil. 



Syngonanthus humboldtii var. elongatus Moldenke, var. nov. 



Haec varietas a forma typica speciei recedit ramis 30-50 cm. longis, verticel- 

 lis foliorum 14-21, et ramis saepe brachiatis. 



TYPE: on Savanna No. Ill, 125 m. alt., Cerro Yapacana, Rio Orinoco, Ama- 

 zonas, Venezuela, January 1, 1951, B. Waguire, R. S. Cowan & J. J. Wurdack 

 30558. New York Botanical Garden. 



Syngonanthus humboldtii var. glandulousus Gleason. 



Dominant savanna herb, common in wet savanna northwest of base of Cerro 

 Moriche, 150 m. alt., Rio Ventuari, Waguire, Cowan & Wurdack 30985. The 

 variety is known also from the lowland savannas about Cerro Duida (Steyermark 

 57857, Tate 315), Auyan-tepul (Tate 1308), and San Fernando de Atabapo (Holt & 

 Gebriger 234). 



Syngonanthus humboldtii var. macrocephalus Moldenke, var. nov. 



Haec varietas a forma typica speciei recedit capitulis 7-9 mm. latis et pedun- 

 culis densiuscule albido-pilosis, pilis irregulariter adpressis saepe contortis non 

 glanduliferis. 



TYPE: in depressions in rocks on the southeast slopes of North Mountain, 

 5000 to 6000 feet alt., Cerro Sipapo (Paraque), Amazonas, Venezuela, December 

 12, 1948, B. Waguire & L. Politi 27649; New York Botanical Garden. A second 

 collection is Waguire & Politi 27796 from bogs near the summit of West Peak, 

 5300 feet alt. 



