Monographs Details: Arcytophyllum aristatum Standl.
Authority: Mena V., Patricio. 1990. A revision of the genus Arcytophyllum (Rubiaceae: Hedyotideae). Mem. New York Bot. Gard. 60: 1-26.
Description:Species Description - Subshrubs prostrate, stoloniferous, mat-forming, stems glabrous. Stipules decurrent, forming a continuous ribbed sheath, with two slender hornlike teeth, (0.7-)0.8-1.2(-1.3) mm long, persistent, glabrous, sometimes 1-several lesser teeth between them. Leaves sessile, entire, (4-)4.5-5(-6) X (1-)1.2-1.5(-2) mm, elliptic or slightly ovate, slenderly aristate, glabrous, midvein abaxially prominent, adaxially depressed, margins abaxially somewhat thickened. Flowers solitary, sessile; calyx lobes equal, erect, acuminate, 1.1-1.5(-1.7) X 0.3 mm, glabrous, intercalycine teeth present, ca. 0.3 mm long; corolla abaxially purplish or bluish, adaxially white, lobes deltate, (1.5-)1.8-2 X 1.8-2 mm, glabrous; tube (2.8-)3-3.2 mm long, glabrous; stamens four, protruding 1 mm from tube, adnated to tubular throat; anthers blue, 1 mm long, 0.3 mm wide; filaments 0.5 mm long; style 2 m m long; stigma 0.4 mm long. Capsules globose, (1-)1.5-2(-2.2) mm in diam.; seeds 4-10 per locule, irregularly cymbiform or pyramidal.

Distribution and Ecology - Distribution. Departments of Risaralda, Cauca, Tolima and Narifio in Colombia and in the provinces of Carchi, Imbabura, Tungurahua and Napo in Ecuador; only one collection from as far south as the province of Chimborazo (Fig. 3 A ).

Discussion:Arcytophyllum aristatum Standley, Publ. Field Columbian Mus., Bot. Ser. 7: 36-37. 1930. Type. Colombia. Caldas: Paramo de Quindio, 3700-4200 m, 15-20, Aug 1922, F. W. Pennell & T. E. Hazen 10003 (holotype, US!; isotypes, G, GH!, NY!, YU). Arcytophyllum aristatum is usually found as creeping and small cushion-forming plants in soil, especially on eroded and pronounced slopes. It is easily distinguishable from Arcytophyllum muticum by its hornlike stipules and by the long aristae at the tip of the leaves.
Distribution:Colombia South America| Ecuador South America|