Ecology. Lowland to upper montane forest; on trunk and branches of treelets and trees, tree ferns, infrequently found on upright dead tress, humus or leaf litter. Elevation: 80-2925 m (Venezuela: 140-2400 m, Colombia: 80-3500 m, Ecuador: 250-2925 m, Peru: 650-2250 m, Bolivia: 240-2270 m). Distribution: Widespread in the Neotropics.
Acroporium pungens is distinguished by the broadly ovate- to oblong-lanceolate leaves and acuminate leaf apex; A. esmeraldicum is similar is size but the leaf apices are piliferous. This species appears to be far less common in Bolivia than in Colombia or Ecuador. Another Acroporium, A. guianense (Mitt.) Broth., is infrequent in the eastern lowlands (Ecuador, Heikkinen RH-1990-43; Bolivia, Churchill et al. 22186 - both at MO); this taxon is characterized by distinct papillose laminal cells. Florschütz-de Waard (1990, Trop. Bryol. 3: 98) considered Acroporium guianense simply a form of A. pungens, however until detailed studies are provided for the genus, it might be advisable to recognize this taxon at some level. The following variety was described by Brotherus: var. stillicidiorum Broth., Rev. Bryol. 47: 45. 1920. Type: Ecuador. Prov. del Oriente, ad stillicidia loco dicto “Derrumbo” secus viam a Gualaquiza ad Aguacate, 1100 m, Allioni. The description, “Robustiusculum, caespitosum, caespitibus densis, fusco-aureis. Caulis ramis usque ad 7 cm longis, plus minusve ramulosis. Foliae rectiora,” appears to fall within the variation of A. pungens.