Monographs Details: Rhamnus sphaerosperma var. mesoamericana L.A.Johnst. & M.C.Johnst.
Authority: Johnston, Marshall C. & Johnston, Laverne A. 1978. Rhamnus. Fl. Neotrop. Monogr. 20: 1-96. (Published by NYBG Press)
Description:Latin Diagnosis - Rami hornotini dense pubescentes pilis effusis lacteis vel nonnunquam pallide fulvis ad 0.75(-1.0) mm longis; laminae foliorum (3.2-)4.2-11.0(-14.0) cm longae (1.3-)1.8-4.8(-6.2) cm latae 2-3-plo longiores quam latiores margine remote serratae vel crenatae subtus pallidae, griseae vel fere incanae pilis ca 0.5-0.75 mm longis erectis epidermis plerumque facile visibilis interdum tomentosae, nervi conspicui; stipulae 3.0-4.0(-5.0) mm longae; pedunculi breves (raro ad 17.0 mm longi) raro nulli in eadem planta; cupula floralis 1.5-(-2.0) mm longa 2.0-2.5(-3.0) mm lata, flores externe saepe dense pubescentes pilis pallidis; ovarium fructusque glabri.

Description - Shrub or tree (1.0-)2.0-8.0(-15.0) m tall, evergreen. Stems with rare exceptions densely beset when very young with cream-colored or occasionally tawny spreading hairs up to 0.8 mm (rarely 1.0 mm) long, decreasing with age. Stipules 3.0-4.0(-5.0) mm long, tapering from base to apex, beset with hairs, and quickly deciduous. Petioles (0.6-)0.8-1.5(-1.9) cm long and moderately to densely pubescent. Leaf-blades usually coriaceous, (3.2-)4.2-11.0(-14.0) cm long and (1.3-)1.8-4.8(-6.2) cm broad, elliptic or with tendencies toward oblong, obovate, or ovate, 2-3 (or slightly more) times longer than broad; base most frequently cuneate but sometimes rounded; apex with an acumen usually 0.5-0.8(-1.4) cm long; margin most often revolute, less frequently plane, remotely serrate or crenate with teeth usually mucronate; above gray-green or dark and from glabrous to moderately (usually sparsely) beset with more or less appressed hairs up to 0.8 mm long and occasionally in bundles of 2-3 hairs each; beneath pale-colored, grayish or almost hoary, and with hairs usually abundant (a single glabrous specimen from Honduras) but in most cases not enough to obscure the epidermis but enough to touch each other, ca 0.5-0.8 mm long and mostly ascending or erect (when short, matted hairs present and epidermis obscured on some specimens, longer erect hairs also present), often glistening and imparting a velvety feel, and occasionally in bundles; major veins above and beneath conspicuous with moderately dense amounts of hair up to 0.5 mm long extending above margin of sulcate midrib above; secondary veins (6-)8-ll(-12) pairs (most frequently 9). Inflorescence with (4-)6-8(-13) flowers per axil; peduncles usually short (rarely up to 17.0 mm) or absent but rarely absent entirely from any given plant; pedicels 2.0-4.0 mm long; floral cup 1.5(-2.0) mm deep, 2.0-2.5(-3.0) mm broad; sepals ca 1.5 mm long, 1.0-1.5 mm wide; external floral parts usually densely beset with pale-colored hairs; petals ca 1.0 mm long and wide, yellowish, clawed and notched and with hairs along abaxial median; anthers apiculate and enclosed by petals; ovary glabrous. Fruiting peduncles up to 10.0 mm long or absent (rarely absent entirely on any given plant) (secondary peduncles also present on El Salvador collections); pedicels (3.0-)4.0-5.0(-9.0) mm long, densely beset with hairs; floral parts not persistent; drupes sphaerical or slightly prolate, (3.0-)4.0-7.0(-8.5)mm in diam, red when young and darker later, glabrous or almost so (trichomes rarely seen), 3-seeded.

Discussion:Because it is sometimes difficult to distinguish between Rhamnus mucronata and R. sphaerosperma var mesoamericana in areas of geographic overlap, the relationship must be quite close. Doubtful because of close resemblance to R. sharpii are Steyermark 33039 (F) and A. Molina R. & A. R. Molina 12358 (F, NY, US) which were collected in the Guatemalan departments of Jalapa and Alta Verapaz where R. sharpii is found.
Distribution:Mexico North America| Oaxaca Mexico North America| Chiapas Mexico North America| Guatemala Central America| San Marcos Guatemala Central America| Sololá Guatemala Central America| Sacatepéquez Guatemala Central America| Guatemala Guatemala Central America| Honduras Central America| Morazán Honduras Central America| Intibucá Honduras Central America| El Salvador Central America| Santa Ana El Salvador Central America|