Monographs Details: Macrocentrum stipulaceum Wurdack
Authority: Maguire, Bassett & Wurdack, John J. 1958. The botany of the Guayana Highland--Part III. Mem. New York Bot. Gard. 10: 1-156.
Family:Melastomataceae
Description:Latin Diagnosis - M. parvulo Gleason affinis sed foliis plusminusve acuminatis distincte denticulatis, ramulis ad nodos cum processibus reniformibus stipulaceis armatis. Herba parva ad 15 cm alta, caulibus glabris. Folia opposita aequalia vel paulo inaequalia; petiolus gracilis glaber 5-15 mm, cum processu reniformi stipuliformi sparse glanduloso-strigoso 1-2 X 1.3-2.5 mm subtentus processibus subpersistentibus 2 (-3?) per nodum; lamina tenuissima 15-40 X 10-20 mm. ovata apice gradatim hebeti-acuminata basi paulo (1-3 mm) cordata, 3-5-nervia, ad margines obtuse dentieulata dentibus ca. 0.1 mm altis 1-2 mm inter se distantibus in dentis sinu ciliata ciliis gracilibus 0.5-1 mm longis, supra et subus sparse strigulosa setis gracilibus ca. 1 mm longis ea. 1/mm2 praecipue praeter venas venulasque. Pedunculi terminates 1-3 cm longi, glabri, 1- vel plerumque 2-flori. Flores ignoti; pedicelli fructuum ca. 5 mm longi. Ilypanthium (ad torum) ca. 4.5 mm longum paulo 8-venosum; calycis lobi interiores quattuor obtusi, ca. 0.7 X 1-3 mm, dente exteriore acuto ca. 0.4 mm projecto, setis paucissimis glanduloso-capitatis ad 1 mm longis extus in calycis lobis notatis. Semina cum aspectu M. gracilis, ca. 0.8 X 0.6 mm, minute tuberculata.

Discussion:

Type: delicate annual, locally frequent in dry places under overhanging rocks on montane slopes of Mt. Ayanganna, elev. 1000-1500 m. British Guiana, Feb 5-6, 1955, Bassctt Maguire, W M. C. Bagshaw, d- Celia K. Maguire 40582 (NY).

M. parvuluin has shorter stems, obtuse to subaeute leaf-blades with obtuse to broadly acute bases, and no stipuliform cauline appendages. The leaf shape, lack of stipules, and many-flowered inflorescences will distinguish M. montanum Gleason and depauperate specimens of M. cristaium Tr. and M. fruticosum Gleason.