Trees, or large shrubs, 2-6(-10 or 15) m tall.  Bark light or more often dark gray, rough, appearing checkered with iso-diametric, rectangular segments or plates 1-2 cm long and 2/3 as wide on the bole and limbs of approximately 6 years and older;  twigs of the previous seasons with outer bark shed in small, roughened flakes;  vestiture of all axes of the current season's growth, including petioles [where most apparent] and leaf surfaces, usually with hairs of 2 kinds: 1) the longer up to 4.7(-5.2) mm, averaging ca 2.5 mm, flexuous, often straight and disposed more or less at right angles, rusty-colored when young, becoming clear, with reddish or yellowish glandular tips, the glands short clavate, rarely spherical, often infected by a fungal anamorph [Sirosporium antenniforme (Berk. & Curtis) Bubak & Serebrianikow] that renders the glands black and gives the specimens a speckled or dotted appearance; 2) the shorter hairs glandless, curly, producing a thinly tomentose indument.  Leaves olive-green above, markedly lighter green beneath, ovate or elliptic, (2-)4.5-6.5(-9) x (1.5-)2-3(-5.5) cm, the longer and wider blades on sterile shoots, basally variably tapered, rounded, truncate, or slightly cordate, apically acute, often with a small (1-2 mm) cusp or short-acuminate tip (rarely obtuse and lacking a cusp), the margins finely serrate, especially on sterile shoots (coarsely toothed on sprouts), sometimes minutely serrate or smooth on fertile shoots, upper surface usually slightly glossy, especially when fresh, glabrous except along the midrib where the glandular hairs shorter than on the young twigs, diminishing in size and density distally, lower surface fleetingly floccose on newly emerged leaves, tomentum sometimes persisting on blades of sterile shoots, then tan or brown;  petiole 1.2-2.7 cm long, conspicuously glandular hairy.  Inflorescence a terminal cluster of racemes, these sometimes densely branched, axes, including the pedicels, densely glandular hairy.  Flowers borne obliquely erect on slender, glandular-hairy, accrescent pedicels up to 1.1 cm long at anthesis, subtended by a dark reddish bract, ca. 2.8 mm long, enclosing two smaller bracteoles;  calyx at first cupulate, the lobes scarious-margined, obtuse or rounded at the apex;  corolla creamy white or yellowish, drying to pale yellow or tan, 5.2-6.3(-7.2) mm long, developing a post-anthesis circumferential dimple at about midway its length, the lobes imbricate with auriculate margins;  stamens with anthers 1.3-1.5 mm long, bearing a pair of very finely tuberculate spurs 1/3-1/2 the length of the thecae;  ovary producing 2-several ovules per locule.  Fruit to 8.5 mm diam.;  seeds  averaging 2.1 mm long.

     Distribution.  From about 27°22'N in the State of Chihuahua, southward through the Sierra Madre Occidental into Jalisco, thence eastward along the northern slopes of the Sierra Volcánica Transversal to extreme western Veracruz, the southernmost locality in the State of México, SW of Distrito Federal, about 18°45'N.  In the montane zone with Pinus and Quercus;  1500-2850 m.  Flowering as early as November, reaching a peak in March;  fruiting (February-)April-June. o specimens seen in flower nor fruit during August and September.

     Vernacular name:  Madroño is used frequently.  Additional names recorded in herbaria are: Madroño Negro, Madroño Chino, and Et'-pi-da-mi-ha-rao-da-fam-i (Hartman 526, GH).