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 on the prostrate branches, coriaceous, elliptic to spatulate, oblanceolate or obovate, to 2.4 x 1.2 cm but typically smaller, basally cuneate to attentuate or rarely obtuse, apically obtuse, rounded or acute, sometimes apiculate, margin 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, racemose, short, to ca. 1.5 cm long, dense, 5-6(-8) flowers;  rachis ca. 4 mm long, puberulent;  floral bracts lanceolate, acuminate, to ca. 6 x 2 mm, puberulent with eglandular or glandular trichomes;  pedicels 2.5-3 mm  long, glandular puberulent to nearly glabrous;  bracteoles basal, ca. 1 mm long. Flowers 5-merous; calyx lobes broadly triangular to suborbicular, obtuse, 1.5-2.0 x 1.5-2.0 mm, more or less glabrous, ciliate, reddish or with band of red pigment distally;  corolla urceolate, 5-6 x 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 suborbicular, ca. 1 x 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 x 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 um diam. (LM);  ovary smooth, glabrous, sessile, weakly 10-lobed or ribbed;  nectariferous disk at base of ovary;  style 2.2-2.5 x ca. 0.8 mm;  stigma slightly lobed, ca. same diameter as style.  Fruit drupaceous, depressed globose, 6-7 mm diam., smooth, glabrous, shining, red at maturity;  nutlets (5?-)7, separable, cariate, 3-4.2 x 1.9-2.5 mm, surface roughened;  n=13 (Niehaus & Wong, 1971).

     Distribution.  Known only from four volcanoes (Acatenango, Agua, Fuego, and Zunil) and the Sierra de los Cuchumantes mountain range of Guatemala.  This endemic subspecies represents a dramatic disjunction, the species being absent from all of Mexico, the closest occurrence of another subspecies of A. uva-ursi being in New Mexico.  Habitats include volcanic summits, steep volcanic slopes, rocky roadside exposures, juniper thickets, and Pinus, Juniperus, and Cupressus forests at elevations ranging from 2440-3750(-3900[?]) m.  See Diggs (1995) for additional information about ecology.  Flowering: Jan (numerous collections)-Sep; fruiting: Jul-Jan.