Monographs Details: Macrocentrum rubescens Gleason
Authority: Maguire, Bassett, et al. 1953. The Botany of the Guayana Highland. Mem. New York Bot. Gard. 8 (2): 87-160.
Description:Species Description - Planta parce ramosa, suffruticosa, caulibus sparse minuteque glandulosis, ad nodos setosis, ceterum glabris; folia petiolata, ovato-lanceolata vel elliptica, obtusa, sparse ciliata, 1-nervia; flores 4-meri, solitarii, breviter pedunculati; stamina isomorpha; antherae subulatae, connectivo infra apicem filamenti in calcar breve dorsale producto.
Species Description - Stems suffruticose, 5-20 cm. tall; internodes up to 3 cm. long, reddish, glabrous except for a few minute sessile glands; nodes bearing 2 pairs of bristles 1-4 mm. long. Petioles slender, up to 4 mm. long, channeled above, reddishglandular. Blades isomorphic, ovate-lanceolate or elliptic, up to 25 mm. long and 10 mm. wide, obtuse, at base acute or somewhat cuneate, sparsely ciliate, glabrous or very sparsely pilose above, glabrous and somewhat paler beneath, 1-nerved. Peduncles solitary, 1-flowered, 2 mm. long, strongly 3-angled, bearing 2 subulate bracteoles at the summit. Flower sessile, 4-merous. Hypanthium obconic, 3.3 mm. long, 8-winged, each wing bearing 2 or 3 short cilia. Calyxtube 0.5 mm. long; sepals somewhat flaring, broadly depressed-semicircular, much wider than long, very thin and minutely erose toward the summit. Stamens isomorphic; filaments slender but flat; anthers subulate, 3.3 mm. long; thecae straight, 2.4 mm. long; connective prolonged 0.4 mm. to the summit of the filament and below the filament into a straight retrorse spur about 0.5 mm. long.
TYPE: cliffs in wet montane mossy forest, Phelps Camp to North Savanna, Cerro Sipapo, Bassett Maguire & Louis Politi 27761; New York Botanical Garden. Paratypes, Cerro Sipapo: Maguire & Politi 27504, 27538, 27620, 27621, and 27874. The species is apparently well distributed on the mountain from the base of the escarpment to the summit and was collected six times by Dr. Maguire.