Holodiscus dumosus (Nutt.) Heller

Sericotheca dumosa (Nutt.) Rydberg
spiraea discolor Torr. Ann. Lye. N. Y. 2 : 195. 1827. Not Spiraea discolor Pursh, 1814.
Spiraea ariaefolia discolor 'X:, & G. Fl. N. Am. 1 : 416. 1840.
Spiraea dumosa Nutt.; T. & G. Fl. N. Am. loc. cit.. as a synonym. — Hook. London Jour. Bot. 6 :
217. 1847. Spiraea discolor dumosa S. "Wats. Bot. Calif. 1 : 170. 1876. Schizonoius argenteus dumosus Kuntze, Rev. Gen. 226. 1891. Holodiscus discolor dumosa Dippel, Handb. Laubh. 3 : 508. 1893. Schizonoius dumosus Koehne, Deuts. Dendr. 265. 1893. Holodiscus dumosus Heller, Cat. N. Am. PI. 4. 1898. Holodiscus australis Heller, Bull. Torrey Club 25 : 194. 1898. Schizonoius discolor dumosus I^ehder, Cycl. Am. Hort. 1629. 1902.
A shrub, 6-10 dm. high; bark of young twigs light-brown, villous, that of the older branches chestnut or dark-gray, exfoliating ; petioles 2-10 mm. long ; Jeaf-blades obovate, 2-5 cm. long, obtuse or acute at the apex, cuneate at the base and decurrent on the petioles, often double-toothed above with broadly rounded-ovate teeth, green and more or less shorthairy above, white and densely villous and tomentose beneath ; inflorescence usually twice compound, ovoid or conic, 5-20 cm. long, 5-10 cm. wide, with ascending or spreading villous branches ; sepals ovate or lance-ovate, 1.5 mm. long; petals elliptic or oval, about 2 mm. long ; stamens about 20 ; pistils 5 ; carpels about 1.5 mm. long, their beaks 1 mm. Holodiscus australis is the form with thinner, more acutish leaf-blades, and more simple toothing.
Type locality : Stony and sandy places of Platte River.
Distribution: Mountains from Wyoming and Utah to New Mexico and Chihuahua.