Holodiscus argenteus var. velutinus (Rydb.) F. A. Ley

Sericotheca velutina Rydberg, sp. nov
A tall shrub, 1 m. or more high; bark of young twigs dark-gray and tomentose, that of the old stems dark-gray or purplish, almost black, exfoliating ; leaf-blades oval-cuneate or spatulate, acute at the apex, cuneate and decurrent on the short petioles, green and finely velvety above, whitetomentose and villous beneath, 1.5-3 cm. long, serrate above the middle with lanceolate, long-mucronate teeth directed forward ; inflorescence narrow, 5-10 cm. long, with a few short spreading branches ; sepals broadly ovate, acute, 2 mm. long ; petals broadly obovate, nearly 2.5 mm. long; stamens 20^ scarcely equaling the sepals; carpels obliquely obovate, that is, the upper edge also curved, although less so than the lower.
Type collected in the Sierra de San Felipe, State of Oaxaca, Mexico, Sept. 25, 1894, Charles L. Smith 821 (herb. N. Y. Bot. Gard.).
Distribution : Southern Mexico and Guatemala.