Comarostaphylis polifolia (Kunth) Zucc. ex Klotzsch

  • 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 polifolia (Kunth) Zucc. ex Klotzsch

  • Type

    Type. Mexico. Guanajuato: Near Villalpando, 2433 m, Humboldt & Bonpland s.n. (holotype, P, n.v.; isotypes, L-fragments, P, photo Diggs neg. 23). The epithet means "with leaves like those of Polium."

  • Synonyms

    Arctostaphylos polifolia Kunth

  • Description

    Species Description - Erect to spreading or sprawling, often gnarled, evergreen shrubs to small trees, 0.2-4(-6) m tall, capable of stump-sprouting; bark peeling or flaking in small pieces or exfoliating in irregular plates, gray to reddish-brown; young twigs glabrous to tomentose to densely glandular hirsute, trichomes stalked, swollen-headed and glandular or hyaline and eglandular. Leaves coriaceous, linear to elliptic, oblanceolate or oblong, plane or strongly revolute, 2-7.6 × 0.31.9 cm, base tapering to cuneate or rounded, apex obtuse to acute, margins entire or rarely with serrations, upper surface glabrous or with slight pubescence, lower surface glabrous to tomentulose to tomentose, sometimes densely so, pubescence sometimes ferruginous, glandular trichomes sometimes also present, especially along the midrib; petioles 27.5 mm long, with pubescence as on young twigs. Inflorescences racemose, sometimes clustered, at times paniculate, 2.2-11 cm long; rachis, pedicels, floral bracts, bracteoles and calyx puberulent, tomentulose, lightly canescent or glandular hirsute, trichomes glandular or eglandular; floral bracts broadly lanceolate to ovate, navicular or carinate, acute to acuminate, 1.4-7.4 × to 2.6 mm, ciliate or not; pedicels 3-11 (-21) mm long; bracteoles basal to subdistal, 1.6-2.9 mm long, ciliate or not. Flowers with calyx lobes narrowly triangular or ovate-triangular, 1.1-3.1 × 0.9-2.3 mm, acute to acuminate, ciliate or not; corollas 4.9-8.2 × 3-6 mm, glabrous or with slight pubescence, white to pink; lobes 0.9-1.7 × 1.1-2.2 mm wide; stamens 2-3.7 mm long; filaments 1.6-3.3 mm long, villous; anthers 1-1.5 × 0.6-1 mm, spurs 0.4-0.9 mm long; ovary glabrous or with eglandular trichomes, sometimes densely villous; style 2.8-5.4 mm long, glabrous or with eglandular trichomes. Fruit red when immature, dark purple to black at maturity, 4-9 mm in diam.; seeds 1.6-3 × 1.1-1.4 mm, surface reticulate.

  • Discussion

    As well as being the most widespread, C. polifolia is also one of the most morphologically variable species in the genus. As noted by Henrickson (1981), Standley (1924) combined five of Small’s (1914) species into his Arctostaphylos polifolia. Standley’s (1924) circumscription is thus very broad and includes specimens with a wide variety of morphological differences, including radical variation in pubescence, leaf shape, and growth form. While my delineation of C. polifolia (Diggs, 1981, 1986b) differs substantially from that of Standley (1924), the species is still quite variable in terms of vegetative characters. Because of the paucity of variation in floral structure in the genus as a whole and particularly in C. polifolia, differences in vegetative morphology- especially leaf shape, inflorescence size, and pubescence of various organs-are of primary importance in separating the subspecific taxa.

    Comarostaphylis polifolia is most closely allied to C. glaucescens, and individuals of the latter are consistently misidentified as C. polifolia. On the basis of numerical studies and field observations, I have concluded that the two are distinct (Diggs, 1981, 1986b, 1987). While a few specimens, usually depauperate, are difficult to place in the correct species, C. polifolia and C. glaucescens are well marked entities easily distinguished by a number of characters including the smaller, often revolute leaves, white to pink rather than red corollas, and more shrubby (vs. tree-like) growth habit of the former (Diggs, 1986b). Determination of the correct epithet for the taxon is problematic, as there is difficulty in the specific assignment of the Humboldt and Bonpland type. The type specimen and the illustration (Kunth, 1819) most closely match the revolute, small-leaved species with white to pink corollas. I have therefore assigned the name C. polifolia to this taxon (Diggs, 1986b). However, while Kunth’s description for the most part matches this species, the corollas are described as "coccinea" or scarlet, like those of C. glaucescens. One explanation for the discrepancy may be the brownish-red tinge often seen upon drying in the white, pink, and red corollas. Another possible explanation is infection of the corollas by parasitic Diptera, which in Oaxaca are known to cause abnormal, often permanently closed, scarlet corollas (Fig. 16B) in C. polifolia subsp. polifolia (Diggs, 1981, 1986b).

    Distribution and Ecology: Comarostaphylis polifolia is the most widespread species in the genus, extending from Oaxaca north and west to Coahuila and Chihuahua, Mexico. It is typically found in "Matorral Xerofilo" (Rzedowski, 1978), or in dry pine or oak-pine forests at elevations of 1500-2800(-2950) m. The species occurs on a variety of soil types, including ones derived from limestone. According to Rzedowski (1978), in some areas C. polifolia can play an important role in the successional sequence leading to reestablishment of oak forests. Flowering and fruiting throughout the year but most commonly Apr- Sept and Jul - Nov, respectively