Monographs Details: Miconia argyrophylla subsp. gracilis Wurdack
Authority: Maguire, Bassett & Wurdack, John J. 1961. The botany of the Guayana Highland--part IV (2). Mem. New York Bot. Gard. 10: 1-87.
Family:Melastomataceae
Description:Latin Diagnosis - Rami juniores obtuse quadrangulati, vetustiores subteretes. Inflorescentiae ramuli ex axe primario graciles ad basim ca. 0.4—0.5 mm diam.

Distribution and Ecology - BRAZIL: Amapa: Serra do Navio, frequent in lowland forest along trail to Rio Araguary; tree 4 m tall, flowers white; 19 Nov 1954, B. S. Cowan 38428 (holotype, NY); Serra do Navio, Cowan 38345, 38380 (paratypes). Para: Akarai Mts. in Rio Mapuero drainage, A. C. Smith 2933; Akarai Mts., Imaibau hills, Guppy 533 (Brit. Guiana For. Dep. 7548) (paratypes). SURINAME: Rikenau Hill No. 3, vicinity of Moengo, Cowan 38973 (paratype). BRITISH GUIANA: basin of Essequibo River near mouth of Onoro Creek, A. C. Smith 2678 (paratype).

Discussion:In typical M. argyrophylla (including var. attenuata Cogn.), the branches are acutely quadrangular and the inflorescence branches 0.7-1 mm diam. M. crassinervia Cogn. was placed by Cogniaux in sect. Ghaenanthera; the Flora Brasiliensis illustration shows anthers longitudinally rimose basally but not apically. I have examined two sheets of the type collection (Riedel 1396, K, W) and cannot distinguish them from Guiana specimens ascribed to typical M. argyrophylla; the anther clefting seems to be caused by drying and/or pressing, rather than a genetic mechanism, and occurs sporadically in Guiana collections of M . argyrophylla sensu Cogniaux. Martius synonymized M. stenostachya D C . with M . argyrophylla and illustrated flowering material of M . stenostachya (Nov. Gen. Sp. Plant. S: fig 284). Unfortunately the type collection of M . argyrophylla is fruiting and I have not as yet been able to compare the holotype with recent flowering material. So many Miconia species have the same gross aspect as M . argyrophylla that the absolute synonymization of M. crassinervia is deferred.