1953} 



BOTANY OF THE GUAYANA HIGHLAND 



133 



MELASTOMACEAE 26 



Rhynchanthera grandiflora (Aubl.) DC. 



Marsh, Puerto la Cruz to Santa Barbara Camp, State of Monagas, Maguire, 

 Kunhardt & Politi 21214a, Usually at low altitudes, French Guiana to eastern 

 Colombia and southward to Bolivia. 



Aciotis laxa (Rich ) Cogn. 



Annual with pink flowers, near Base Camp on Rio Cuao, Maguire & Politi 

 27366. A common species of the Amazonian rain forests. 



Aciotis purpurascens (Aubl.) Triana. 



Annual with pink flowers, near Base Camp on Ri'o Cuao, Maguire & Politi 

 21361. The commonest species of the genus throughout the Amazonian rain 

 forests. 



Desmocelis villosa (Aubl.) Naud. 



Annual with pink petals, moist grassy places, sandy soil along stream, under 

 Mauripa, State of Monagas, Maguire, Kunhardt & Politi 21296. Widely distributed 

 at low altitudes in tropical South America. 



Macairea rigida Benth. 



Shrub up to 2 m. tall with purple or red petals, on Cano Profundo, Cerro Si- 

 papo, Maguire & Politi 28324; on Cerro Culebra of Cerro Duida, altitude 1440 m., 

 Maguire & Maguire 29105; on a ridge of Cerro Marahuaca, altitude 1350 m., Ma- 

 guire & Maguire 29166. Endemic to the mountains of southern Venezuela. 



Acisanthera recurva (Rich.) Griseb. 



Annual, petals purple, stamens dark purple, under Mauripa in sandy soil, moist 

 grassy places along stream, State of Monagas, Maguire, Kunhardt & Politi 21291. 

 Widely distributed in tropical South America, mostly at low altitudes, also in 

 Costa Rica. 



Comolia lythrarioides (Steud.) Naud. 



Subherbaceous perennial up to 5 dm. tall, flowers purple, mossy wet banks 

 along rocks, Danta Falls, Rio Cuao, Maguire & Politi 21351. Venezuela, Trini- 

 dad and the Guianas. 



Comolia villosa (AubL) Triana. 



Weak subshrub up to 5 dm. tall, flowers pink, Murcielago Falls, Rio Cuao, 

 Maguire & Politi 21311. Lowlands of Venezuela and. the Guianas. 



Tibouchina striphnocalyx (DC.) Gl. 27 



An abundant shrub up to 3 m. tall at several locations on Cerro Sipapo, Ma- 

 guire and Politi; wet ledges and cliffs, precipitous east slopes, 1440 m., 21830; 

 along water course, upper East Basin, 1500-1650 m., 28463; upper Carlo Negro 

 and north branch of Cano Profundo, 28263; western slopes, 1650 m., 21600; 

 flowers purple, shrub 2 m. high, occasional, Upper Camp Savanna, 1500 m., 

 28694. The flowers were noted once as purple and once as white. Endemic to this 

 general region. 



Tibouchina kunhardtii Gl. 



A common shrub in wet ground on the summit of Sipapo, Maguire & Politi; 

 marsh about pool, Cano Negro, 21113; border of thickets near the summit, 28126; 



26 by H. A. Gleason. 



"For a review of the genus, see H. A. Gleason, The Genus Tibouchina in southern 

 Venezuela (Phytologia 3: 238-243. 1950). 



