Several large collections made during the 1957-58 Neblina exploration have slightly altered the circumscription of this species. These recent specimens show cauline pubescence often pale and styles often glabrous. These two variables are combined in parts of the collections in all four possible permutations; no infraspeciflc distinctions seem warranted. This variability, however, does not alter the basic distinctions from M. rigida Benth. enumerated in the original description of M . neblinae.