Comarostaphylis discolor subsp. rupestris (B.L.Rob. & Seaton) Diggs

  • 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

  • Scientific Name

    Comarostaphylis discolor subsp. rupestris (B.L.Rob. & Seaton) Diggs

  • Type

    Type. Mexico. Michoacan: Dry rocky hills nr. Patzcuaro, 14 Oct. 1892 (bud, fl), Pringle 4318 (lectotype [Diggs, 1986b], GH, photos Diggs neg. 13 & NY neg. 9763); isotypes, A, BM, BR, BR-fragment, F, G, LE, M, MO, MSC, NY, P, PH, n.v., RSA, UC, US, VT, W). The epithet rupestris, denoting rocky or rock-dwelling, was apparently chosen based on the habitat, described on the type collection as "Dry rocky hills."

  • Synonyms

    Arbutus spinulosa M.Martens & Galeotti, Arctostaphylos rupestris B.L.Rob. & Seaton, Comarostaphylis rupestris (B.L.Rob. & Seaton) Small, Arbutus spinulosa M.Martens & Galeotti, Arctostaphylos spinulosa M.Martens & Galeotti

  • Description

    Subspecies Description - Plants 1-5 m tall; young twigs and petioles tomentulose or tomentose. Leaves plane; upper surface glabrous or with scattered eglandular trichomes, green and shining or somewhat dull, lower surface tomentulose to densely ferruginous-tomentose, becoming less so with age. Inflorescences tomentulose to tomentose, trichomes eglandular. Flowers with corollas glabrous or with eglandular hyaline trichomes.

  • Discussion

    The epithet spinulosa (basionym: Arbutus spinulosa Martens & Galeotti) (McVaugh & Rosatti, 1978) is available at the subspecific rank and is the oldest specific epithet for the taxon. However, because of the potential for confusion with C. spinulosa subsp. spinulosa (basionym: Arctostaphylos spinulosa), and because priority applies only within a rank (Voss et al., 1983), the next available epithet, rupestris, was chosen (Diggs, 1986b).

    The entity here treated as subsp, rupestris has long been recognized as a separate species (Robinson & Seaton, 1893; Small, 1914; Standley, 1924). However, with the exception of the tomentulose to densely ferruginous-tomentose leaves and twigs (becoming less so with age) versus glabrous, and the tomentulose to tomentose but non-glandular inflorescences versus glabrous or with glandular trichomes, there is no consistent character by which to distinguish it from subsp. discolor. Numerous field observations of both taxa support the reduction to the subspecific level. Furthermore, numerical analyses using various continuous characters show a morphological gradient with extensive overlap between the two extremes (Diggs, 1987). While allopatric over most of their ranges, these two subspecies of C. discolor occur in apparently mixed populations near Aguililla, Michoacan [McVaugh 22840-22843 (ENCB, MICH)].

    Distribution and Ecology: Comarostaphylis discolor occurs in the mountains of central Mexico from Jalisco east to Hidalgo and Veracruz, and south through the mountains of Oaxaca and the central highlands of Chiapas into E Guatemala. The species is known from elevations of approximately 1850-3300(-3900) m in open or disturbed areas or in the understory of mesic montane forests. Flowering and fruiting throughout the year.

  • Objects

    Specimen - 9778, C. G. Pringle 4318, Arctostaphylos rupestris B.L.Rob. & Seaton, Ericaceae (261.0), Magnoliophyta, isotype; North America, Mexico, Michoacán

  • Distribution

    Mexico North America| Michoacán Mexico North America|