Aulomyrcia karuaiensis Steyerm., Fieldiana Bot. 28: 1005. 1957.
In 1958 this species and M . maguirei McVaugh were contrasted as follows:
Plants (except the vegetative buds) completely glabrous; leaves 1.5-2.5 cm wide, elliptic,
2.3-3 times as long as wide. M. karuaiensis.
Young shoots and inflorescence thinly pubescent; leaves 0.3-1.6 cm wide, mostly lanceolate,
4-9 times as long as wide. M. maguirei.
This key served to separate two species known from two collections each, especially
as the two were from widely separated localities. N o w one additional specimen
from each region is at hand, and it seems that the two supposed species are more
alike than originally supposed. The original collections of M . karuaiensis were from
Ptari-tepui and Apacara-tepui, respectively; the following collection, from the same
general region, would key out above to M . maguirei except that the herbage is
quite glabrous: V E N E Z U E L A . Bolivar: Auyan-tepui, along Rio Churun, elev 1660
m, 12 M a y 1964 (fl), Steyermark 93765 (MICH).
The following collection, from a cerro on which M . maguirei might be expected,
has the pubescence of that species but the leaves 3-4 times as long as wide; that is,
relatively broader than in the original specimens: V E N E Z U E L A . Amazonas: Cerro
de la Neblina, Cafion Grande E of Cumbre Camp, elev 1100 m, 24 Nov 1957 (fr),
Maguire et al 42201 (MICH).
In summary, the differences between Marlierea karuaiensis and M . maguirei are
almost nonexistent; in the latter the young herbage (not the mature leaves) is
sparingly pubescent; and in the former the leaves are sometimes (but not always)
elliptic and obtuse. I suspect that when more material becomes available, the two
species may properly be united taxonomically.