Erect shrub 0.2-1.5 m tall with stems, twigs, leaves, and petioles usually glaucous;  mature stems terete, striate, glabrous, sometimes ± nitid;  bark reddish-gray, cracking and then exfoliating in thin, narrow strips;  twigs subterete, bluntly angled, striate, glabrous or white puberulent, sometimes when puberulent also moderately to densely hirsute with thin, straight or crisped, eglandular or minutely gland-tipped hairs 0.5-1 mm long, these sometimes deciduous and then leaving punctae;  buds small, scales ovate, striate, maroonish, glabrous or weakly puberulent, ciliolate.  Leaves subcoriaceous, ovate, ovate-oblong, or elliptic-oblong, (2-)3-5.5(-6.8) x (1.1-)1.7-2.5(-3) cm, base rounded, truncate or shallowly cordate, apex acute to shortly and sometimes abruptly acuminate, margin thinner than lamina, weakly serrulate to somewhat serrulate-crenulate, with each tooth terminating in a deciduous, short, gland-tipped hair (or subentire), glabrous or weakly puberulent above and also sometimes with scattered, crisped, eglandular, ferruginous hairs, beneath glabrate with punctae or weakly to densely hirsute with tiny, crisped, eglandular or gland-tipped ferruginous hairs, (these ± persistent);  midrib impressed or slightly raised distally above and raised beneath, lateral nerves 4-7 per side, weakly impressed or weakly but conspicuously raised above and raised beneath, reticulate veinlets weakly impressed to weakly but conspicuously raised above and raised beneath;  petiole subterete, broadly canaliculate above, rugose, 2-5 mm long, glabrous or pubescent as twigs.  Inflorescence racemose, (3-)9-21-flowered, one collection showing a solitary-flowered inflorescence along with racemes; rachis complanate, bluntly angled, 2-7 cm long, glabrous or puberulent and/or then sometimes also hirsute with short-stalked glands or thin, straight to crisped, eglandular or minutely gland-tipped, ferruginous hairs, sometimes glaucous;  pedicels subterete, bluntly angled, 3-10 mm long and after anthesis elongating to 18 mm, glabrous or puberulent as rachis;  bracteoles subopposite, located near base of pedicel, linear-ovate, 3-5 x 1-3 mm, acuminate to acute, glabrous or puberulent, ciliolate and marginally bearing minutely gland-tipped hairs;  floral bract subcoriaceous, cochleariform, striate, ovate to oblanceolate, (4-)6-11 x 3-4 mm, acute to acuminate, glabrous or puberulent, ciliolate, sometimes also with scattered, tiny, gland-tipped, ferruginous hairs dorsally.  Calyx 4-6 mm long, sometimes very deeply lobed, glabrous or puberulent, sometimes also weakly to densely glandular pubescent with straight or crisped, ferruginous hairs, lobes smooth or striate, narrowly triangular to ovate, 2.5-4.5 x 1.6-2.2 mm, acuminate;  corolla (4.5-)6-7.5 x ca. 6 mm, whitish-rose when fresh, glabrous or puberulent, also sometimes densely strigose with crisped, eglandular or glandular, white to ferruginous hairs, lobes ovate-triangular, ca. 1 mm long, obtuse;  stamens 3.2-4.5 mm long (but few available to measure);  filaments 2-2.6 mm long, glabrous or puberulent;  anthers 1.6-2.5 mm long, the awns conspicuous;  ovary glabrous or pilose;  style 4-5 mm long, glabrous or short-pilose at base.  Fruiting calyx 8-9 mm diam., glabrous or weakly hirsute with gland-tipped hairs, reddish- to blue-black.

     Distribution (Map).  Endemic to the dry Pinus, Quercus, Arbutus, and Abies forests of northwestern Mexico in the Neovolcanic and Sierra Madre mountains at elevations of 1800-3200 m.  Flowering seems to be scattered throughout the year but fruiting is more prominent from June to November.
 

                Key to the Varieties of Gaultheria glaucifolia

1.  Plants glabrous;  leaf venation raised on both surfaces;  calyx
     cleft nearly to base, the lobes triangular and striate;  Jalisco
     and Durango ..............................................................  var. glaucifolia
1.  Plants puberulent and weakly to densely glandular hirsute;  leaf
     venation plane to impressed above (sometimes raised) and raised
     beneath;  calyx not usually deeply cleft, the lobes ovate and smooth;
     Chihuahua, Jalisco, Michoacán, Nayarit, and Sonora ..........  var. rosei
 

Gaultheria glaucifolia Hemsley var. glaucifolia.

     Plants glabrous.  Leaves with midrib, lateral nerves, and reticulate veinlets raised on both surfaces.  Calyx deeply cleft nearly to the base, the lobes triangular and conspicuously striate.

     Distribution (Map).  Endemic to Mexico (only from the states of Durango and Jalisco), in Pinus-Quercus forest at 2400-2460 m elevation.  Flowering and fruiting specimens have been collected from Aug to Nov.  Rare and probably endangered.
 

Gaultheria glaucifolia Hemsley var. rosei (Small) Luteyn, Fl. Neotrop. Monogr. 66: 465.  Gaultheria rosei Small, N. Amer. Fl. 29: 79.  1914.  Type. Mexico.  Nayarit:  Sierra Madre, nr. Santa Teresa, 11 Aug 1897 (fl), Rose 2183 (holotype, US, photo Corcoran neg. 49;  isotypes, GH, NY) .  Image: SEM of seed.

     Plants white puberulent and also moderately to densely hirsute with thin, straight or crisped, eglandular or minutely gland-tipped hairs 0.5-1 mm long, these sometimes deciduous and then leaving punctae.  Leaf venation weakly impressed above (rarely raised) and raised beneath.  Calyx not usually deeply cleft, the lobes ovate and smooth.

     Distribution (Map).  Endemic to Mexico (only from the states of Chihuahua, Jalisco, Michoacán, Nayarit, and Sonora), in Pinus (Quercus, Abies, Arbutus) forest up to tree line, at elevations of 1800-3200 m.  Flowering specimens have been collected in Feb, Jun, Jul, Sep, and Nov;  fruiting in Feb and Jun-Nov.

     Common names and uses.  Tara. name:  rokwásori, wasa (Chihuahua). The fruit is reddish-black and sweet and is eaten by goats and people.