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 pungens var. cratericola Donn.Sm., Arctostaphylos cratericola (Donn.Sm.) J.D.Sm., Uva-ursi cratericola (Donn.Sm.) Abrams

Description:

Description - Prostrate, creeping shrubs, rooting along the branches, often forming dense mats. Mature stems 1 m or less long, with shreddy, peeling, grayish-brown to brownish bark; young twigs glabrate or puberulent. Leaves horizontally oriented, coriaceous, elliptic to spatulate, narrowly obovate or obovate, to 2.4 × 1.2 cm but typically smaller, base cuneate to attenuate or rarely obtuse, apex obtuse, rounded or acute, sometimes apiculate, margins entire, puberulent, bifacial, the stomata restricted to the lower surface, upper surface glabrous, lower surface glabrous or sparsely puberulent along midrib; petiole concave abaxially, to 3.5 mm long, sparsely puberulent. Inflorescences terminal, short, to ca. 1.5 cm long, dense, racemose, 5-6(-8) flowers; rachis ca. 4 mm long, puberulent; pedicels 2.5-3 mm long, glandular puberulent to nearly glabrous; bracteoles basal, ca. 1 mm long; floral bracts narrowly ovate, acuminate, to ca. 6 x 2 mm, puberulent with eglandular or glandular trichomes. Flowers 5-merous; with calyx lobes broadly triangular to sub-orbicular, obtuse, 1.5-2.0 × 1.5-2.0 mm, more or less glabrous, ciliate, reddish or with band of red pigment distally; corollas urceolate, 5-6 × 3-3.5 mm, externally glabrous, internally with sparse trichomes to ca. 0.3 mm long, white to pink, the pink sometimes more intense distally, often reddish before anthesis, lobes broadly triangular to sub-orbicular, ca. 1 × 1.5 mm; stamens 10, to 2.1 mm long, filaments swollen near base, to 2 mm long, sparsely villous, anthers 0.8-1.1 × 0.5-0.6 mm, two dorsal spurs 0.9-1.1 mm long, terminal slits or pores to 0.4 mm long, reddish-purple; pollen grains ca. 44-64 µm diam. (LM); ovary glabrous; style 2.2-2.5 × ca. 0.8 mm; stigma slightly lobed, ca. same diameter as style; weakly 10-lobed or ribbed, disk-like nectary at base of ovary. Fruit drupaceous, depressed globose, 6-7 mm diam., smooth, glabrous, shining, red at maturity; nutlets (5?-)7, separable, carinate, 3-4.2 × 1.9-2.5 mm, surface roughened; n = 13 (Niehaus & Wong, 1971).

Discussion:

Standley and Williams (1966) say, "Skutch reports the fruit is insipid."

This taxon was originally described as a variety of A. pungens (Smith, 1891), later recognized as a separate species (Smith, 1913), and more recently (Wells, 1968) treated as a subspecies of A. uva-ursi. Regarding the varied taxonomic disposition of the taxon, Wells (1968) suggested, "The holotype of subsp. cratericola has markedly elliptic leaves, an unusual variation, and this may have been enough to obscure its relationship to A. uva-ursi. "Recognizing the taxon at the subspecific level, Wells (1968) gave several characters separating it from subsp. uva-ursi: "pedicels varying from minutely glandular-puberulent to glabrous, instead of consistently eglandular and usually glabrous; also the leaves vary from spatulate to oblanceolate or elliptic and from apiculate to obtuse at the tip, while subsp. uva-ursi shows leaf shape variation from spatulate to obovate, rarely elliptic, with the leaf tip consistently obtuse, rarely apiculate." According to Stevens (1969), "anatomical studies support the general direction of this latest transfer, although perhaps not the rank." Subspecies cratericola shares a Pieris-type midrib bundle and stomata only on the abaxial surface of the lamina with A. uva-ursi, in contrast to the circular midrib bundle and stomata on both leaf surfaces that occur in A. pungens (Stevens, 1969). Stevens (1969) further indicates that, while clearly related to A. uva-ursi, subsp. cratericola has a number of characters not seen in either A. pungens or A. uva-ursi, including deeper epidermal cells, mucilaginous-type epidermis with a wall periclinally bisecting the cells, and shorter anther spurs. Field observations (Diggs, 1986a, 1987) of subsp. cratericola, as well as A. pungens and A. uva-ursi, support the present taxonomic placement. Growth form (prostrate, creeping), leaf shape, and fruit color (red) are examples of the numerous characters shared by subsp. cratericola and North American populations of A. uva-ursi (in contrast to A. pungens). Electrophoretic data (Diggs, Soltis & Soltis, unpubl.) also support a relationship between the Guatemalan endemic and A. uva-ursi.

Distribution and ecology: Subspecies cratericola is known only from four volcanoes (Acatenango, Agua, Fuego, and Zunil) and the Sierra de los Cuchumatanes mountain range of Guatemala. This endemic subspecies is widely disjunct from the main range of the species, the closest occurrence of another subspecies of A. uva-ursi being New Mexico. Habitats include volcanic summits, steep volcanic slopes, rocky roadside exposures, juniper thickets, and Pinus, Juniperus, and Cupressus forests at 2440-3750(-3900[?]) m elevation. Associates include Alchemilla sp., Cupressus sp., Halenia sp., Juniperus standleyi, and Pinus sp. A number of collections from the Sierra de los Cuchumatanes are from limestone, while all other collections are from igneous substrates. Collections from the Sierra de los Cuchumatanes indicate that subsp. cratericola is occasional to frequent or common in occurence, sometimes even dominant (see also Standley & Williams, 1966). On Volcan de Agua, while being restricted to the crater rim and adjacent open areas and pine forests, the taxon is abundant, with a population composed of hundreds of individuals, and is one of the dominants in the vegetation. Because the plant forms dense mats and long - trailing, rooting branches, it is often difficult to determine the limits of individual plants. Flowering: Jan (numerous collections) - Sept; fruiting; Jul - Jan.

Distribution:

Guatemala Central America| Chimaltenango Guatemala Central America| Huehuetenango Guatemala Central America| Quezaltenango Guatemala Central America| Sacatepéquez Guatemala Central America|

Common Names:

abril