This species is characterized by its tomentellous to strigillose pubescence, medium-sized to robust obovate leaves, stipules 8-20 mm long, subsessile to shortly pedicellate flowers, calyx lobes 0.3-0.8 mm long, corollas 2-4 mm long, and capsules 10-20 x 2 mm. Alseis blackiana has milky sap, at least when juvenile (C.M. Taylor, pers. obs.).  

Alseis blackiana is frequent on Barro Colorado Island in central Panama, and was studied taxonomicaly there by Croat (1978), who presented a description and illustrations, and ecologically there by Tobin et al. (1999). Alseis blackiana is similar to Alseis labatoides, and especially vegetatively to Alseis microcarpa. 

Seasonal to humid or wet forest at 0-500 m in southern Central America, from central to eastern Panama, and across northern Colombia (Antioquia, Caldas, Chocó, Santander).

• Tobin, M. F., O. R. López & T. A. Kursar. 1999. Responses of tropical understory plants to a severe drought: tolerance and avoidance of water stress. Biotropica 31(4): 570–578.
• Croat, T. B. 1978. Fl. Barro Colorado Isl. 1-943. Stanford Univ. Press, Stanford.