Arbutus arizonica (A.Gray) Sarg.

  • Description

    Description: Tree, 3-8(-10) m tall; bark light gray to reddish-gray, checkered with iso-diametric, squarish to rectangular segments or plates, 1-4 x 1-2.5 cm, retained on the bole and major limbs. Twigs three years old and older with brick-red outer bark exfoliating in small flakes or sometimes in slender strips. Leaves crowded, glabrous throughout, olive-green and glossy above, slightly lighter green beneath; blades (2.5-)3-7.5(-9) x (1-)1.8-3(-4) cm, the larger on sterile shoots with long internodes, basally tapered-acute, rarely slightly rounded, blades tending to be overall smaller and more lanceolate or even linear-lanceolate in the northern part of the range, broader and more nearly ovate-lanceolate southward, apically acute, less often slightly acuminate-lanceolate, sometimes ovate, the margins smooth except on sprouts where sometimes coarsely serrate; petiole often red, glabrous, (1-)1.7-3.2(-4.2) cm long. Inflorescence a cluster of racemes, often congested, axes (including pedicels) densely pubescent, the hairs sometimes glandular. Flowers obliquely erect or slightly pendulous on accrescent pedicels reaching 1.6 cm long in fruit, subtended by a scale-like reddish bract, up to 2.4 mm long, enclosing two smaller bracteoles; calyx pale green, cupulate, lobes scarious-margined, obtuse or rounded; corolla creamy white, drying to creamy tan, 5-5.6 mm long, urceolate, developing a circumferential dimple at about midway its length, the dimple becoming less prominent when approaching anthesis, the lobes slightly overlapping, at first erect then becoming reflexed; stamens 10, distinct, attached at the base of a nectariferous disc; anthers averaging 1.4 mm long, finely-tuberculate spurs 1/2-2/3 the length of the thecae; ovary with ovules (2-)3-several per locule. Fruit ripening to a rich blackish-red, 6.5-9 mm diam., varying greatly owing to seasonal conditions; seeds about 2 mm long.

    Distribution: Southeastern Arizona and adjacent New Mexico in the USA and southward through the Sierra Madre Occidental of western Mexico into the State of Jalisco. Riverine forest and parklands along seasonally moist waterways in the northern part of its range, and southward in the seasonally dry montane zone with Pinus, Quercus, Arctostaphylos, and other species of Arbutus; 1300-2800 m. Flowering early March in the south and continuing until May and June in the north, rarely as late as July or August; mature fruit present from August through October. No specimens seen in flower nor fruit November though February.

    Type: U.S.A. Arizona: Pima Co., Santa Rita Mtns, 1375-2150 m, 27 May 1881, Pringle s.n. ( lectotype: A; isolectotypes: CM, DEK, GH, NY).

  • Floras and Monographs

    Arbutus arizonica (A.Gray) Sarg.: [Article] 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.

    Arbutus arizonica (A.Gray) Sarg.: [Article] 1891. Gard. & Forest. 4: 317, fig. 54.