otay manzanita

Arctostaphylos otayensis is an erect or mound-forming shrub, 1–3 m (3.3–9.8 ft) tall. It lacks a burl, and has twigs that are sparsely covered in short hairs and long glandular hairs. The leaves are erect, borne on petioles 5–8 mm (0.20–0.31 in) long. The base of the leaf near the petiole has a rounded or truncate shape. The leaves have a gray-glaucous color and are narrowly elliptic or oblong-elliptic to ovate in shape, measuring 2–3 cm (0.79–1.18 in) long by 1–2 cm (0.39–0.79 in) wide. The inflorescence is a panicle with 4 to 7 branches. The young inflorescence branches have an erect or ascending orientation, and are covered in hairs like those on the twigs. The inflorescence is covered in leaflike bracts. The flowers are attached to pedicels 3–8 mm (0.12–0.31 in) long. The flowers are white, with a conic to urceolate shape, and with an ovary covered in dense white hairs. Flowering is from winter to early spring. The fruits are globose in shape, mostly lacking hairs, and are 6–8 mm (0.24–0.31 in) in diameter.

Arctostaphylos otayensis is mostly restricted to the San Ysidro Mountains of San Diego County, California and Tijuana Municipality, Baja California. Smaller populations occur on neighboring San Miguel Mountain to the north, and to the south near La Misión. A. otayensis is found in chaparral and cismontane woodland habitats in metavolcanic soils, where it occurs on rocky slopes or outcrops. Associates in chaparral include Adenostoma fasciculatum, Arctostaphylos glandulosa, Malosma laurina, Ceanothus, and Chamaebatia australis. In Tecate cypress associations, it occurs with Xylococcus bicolor, A. glandulosa, Cercocarpus betuloides, Comarostaphylis diversifolia, and C. australis. The San Ysidro Mountains are an ancient volcanic system which supports a high number of endemic taxa like A. otayensis possibly limited to the metavolcanic rocks and soils. As this species lacks a burl, it cannot resprout after intense fires.