Monographs Details:
Authority:

Luteyn, James L., et al. 1995. Ericaceae, Part II. The Superior-Ovaried Genera (Monotropoideae, Pyroloideae, Rhododendroideae, and Vaccinioideae P.P.). Fl. Neotrop. Monogr. 66: 560. (Published by NYBG Press)
Family:

Ericaceae
Synonyms:

Arctostaphylos spinulosa M.Martens & Galeotti, Arctostaphylos conzattii Fernald, Arctostaphylos glabrata Fernald, Comarostaphylis conzattii (Fernald) Small, Comarostaphylis glabrata (Fernald) Small
Description:

Subspecies Description - Low, mat-forming to upright shrubs (to small trees?) to 4(-6?) m tall; young twigs and petioles tomentulose by eglandular pubescence. Leaves ferruginously tomentulose below or sometimes tomentose below on the young leaves, rarely nearly glabrate. Inflorescences with rachis, pedicels, bracts, bracteoles and calyx tomentulose by eglandular trichomes.

Discussion:

The small, usually ovate to obovate, serrate, abaxially tomentulose to tomentose leaves, and foliage and inflorescences with eglandular trichomes serve to distinguish subsp. spinulosa. At several localities near Oaxaca (e.g., Sierra de San Felipe; near Autlan), populations are found that include individuals intermediate between subsp. spinulosa and C. discolor subsp. discolor in growth form, leaf size, and pubescence (Diggs & Corcoran 2140, 2327, 2329, 2352), with some of these occurring in what appear to be hybrid populations (e.g., Diggs 2352). The origins and affinities of these populations are not clear.

Several additional unusual populations should also be mentioned. In the mountains south of Oaxaca, there are populations of subsp. spinulosa (Diggs & Corcoran 2312, 2320, Diggs et al. 3874, 3949) that have the typical pubescence of this species but have leaves slightly larger than usual and sometimes reach nearly 3 m in height (resembling C. discolor subsp. discolor). One collection, Diggs et al. 4055, resembles C. arbutoides in leaf shape, in pubescence, and in having some leaves nearly entire. Finally, an isolated collection (Purpus 3249: MO, NY, US) from western Oaxaca resembles C. discolor in overall leaf size and shape, and C. spinulosa in its indumentum, but differs from both by its entire to remotely serrulate leaves.
Distribution:

Mexico North America| Oaxaca Mexico North America|