Holodiscus discolor (Pursh) Maxim.

Sericotheca saxicola (Heller) R,ydberg
Holodiscus saxicola Heller, Muhlenbergia 1 : 41. 1904.
A shrub, about 1 m. high, much branched; bark of the young twigs light-brown, villous; that of the older branches brown or gray, exfoliating; leaf-blades broadly oval, ovate or orbicular, 8-15 mm. long, rounded at the apex, abruptly narrowed into a very short winged petiole, crenate except at the base, bright-green and sparingly pubescent above, grayish-tomentose and slightly villous beneath ; inflorescence 3-10 cm. long, simple or with a few short branches below, villous ; sepals lance-ovate, acute, 1.5 mm. long ; petals almost white, broadly ovate, obtuse, 2 mm. long; stamens about 20, 2 mm. long; pistils 5 ; carpels about 2 mm. long, their beaks 1 mm. long.
Type locality : Among granite rocks at Donner Pass, Nevada County, California. Distribution : Nevada County, Californiii.

Sericotheca discolor (Pursh) Rydberg
spiraea discolor Vvlx^^ F1. Am. Sept. 342. 1814.
Spiraea ariaefolia Smith, in Rees, Cycl. 33 : no. 16. 1819.
Schizonoius discolor Raf. New Fl. 3 : 75. 1838.
Spiraea discolor ariaefolia S. "Wats. Bot. Calif. 1 : 170. 1876.
Holodiscus discolor Maxim. Acta Hort. Petrop. d : 254. 1879.
Schizonoius argenteus ariaefolius Kuntze, Rev. Gen. 225. 1891.
Schizonoius argenteus discolor Kuntze, Rev. Gen. 225. 1891.
Schizonoius ariaefolius Greene, Fl. Fran. 58, in part. 1891.
Schizonoius discolor ariaefolius Koehne. Deuts. Dendr. 265. 1893.
Holodiscus ariaefolius Greene, Man. Bay Reg. 113. 1894.
Holodiscus discolor ariaefolius Jepson, Fl. W. Middle Calif. 277, in part. 1901.
Schizonoius discolor Purshianus Rehder, Cycl. Am. Hort. 1627. 1902.
A shrub, 1-4.5 m. high ; bark of the young twigs light-brown, more or less villous and tomentose; that of the older branches darker, chestnut or purplish, exfoliating; petioles 1-2 cm. long, villous ; leaf-blades rounded-ovate or oval, usually double-toothed with broadly ovate, mucronate teeth, acute at the apex, truncate, rounded or cuneate at the base, but slightly if at all decurrent, 4-10 cm». long, thin, green and sparingly pubescent or in age glabrate above, more or less densely villous and tomentose beneath, in the t5rpical form white, but in the more common form {Spiraea ariaefolia^ merely gTa3dsh ; inflorescence conic or ovate, 10-20 cm. long, 5-15 cm. wide, twice or thrice compound ; branches villous, usually divergent; hypanthium small, saucer-shaped; sepals oblong or lance-oblong, obtuse or acutish, 1.25-1.5 mm. long; petals white, elliptic, 1.5 mm, long or more; stamens 15-20, filaments 2-2.5 mm. long; pistils usually 5; carpels semi-ovate, straight on the inner, strongly curved on the outer margin, 1-5 mm. long with a beak of the same length.
Type locality : Banks of the Kooskoosky.
Distribution : Hills and river-banks, from British Columbia to northern California, Idaho, and western Montana.

Sericotheca boursieri (Carr.) Rydberg
spiraea Boursieri Carr. Rev. Hort. 1859 : 520. 1859.
A shrub, 1 m. high or less, branched from the base; bark of the young twigs lightbrown, densely villous ; that of the older branches dark-gray or brown or nearly black, exfoliating ; leaves 1-3 cm. long ; blades suborbicular or flabelliform, rounded at the apex, abruptly contracted into the short winged petioles, more or less doubly toothed with ovate, mucronate teeth, densely villous on both sides, green above, grayish beneath ; inflorescence 5-7 cm. long, simple or with a few short branches below ; sepals broadly ovate, acute, fully
2 mm. long ; petals oval, a little longer than the sepals ; stamens 20, 2 mm. long ; pistils 5 ; carpels about 2 mm. long, their beaks 1 mm.
Type locality : California.
Distribution : Mountains of California and adjacent Nevada.

Sericotheca glabrescens (Greenman) Rydberg
spiraea dumosa Torr. in Stansb. Kxpl. Utah 387. 1852. Not 5. dumosa Nutt. 1847. Spiraea discolor glabrescens Greenman Erythea 7 : 116. 1899. Holodiscus glabrescens Heller, Muhlenbergia 1 : 40. 1904.
A diffuse shrub, 6-12 dm. high ; bark of young twigs light-brown, sparingly hairy or glabrous, but conspicuously glandular-atomiferous, that of the older branches dull-brown or almost black ; leaf-blades cuneate-obovate, 1-1.5 cm. long, obtuse at the apex, decurrent on the short petioles, evenly toothed above the middle, glabrous or hairy on the veins, glandular-atomiferous and green on both sides ; inflorescence more or less compound, 3-6 cm. long; the branches short and more or less spreading; sepals ovate, acute or shortacuminate, 1.5 mm. long; petals white, oval, 2 mm. long; stamens 20, about 2 mm. long; carpels 1.5 mm. long, their beaks 1 mm. long.
Type locality : Stein's Mountain, Oregon.
Distribution : Mountains from Oregon and northern California to Utah.

Sericotheca microphylla Rydberg
Holodiscus microphyllus Rydb. Bull. Torrey Club 31 : 559. 1904. Holodiscus dumosus C. K. Schneid. Handb. lyaudb. 1 : 497, in part. 1905.
A low diffuse shrub, 3-10 dm. high ; bark of the young twigs light-brown or yellowish, soft-villous, that of the stems dark-brown or gray and exfoliating ; leaf-blades spatulatecuneate, 1-1.5 cm., rarely 2 cm. long, evenly serrate above the middle, obtuse at the apex, cuneate at the base and decurrent on the short petioles, finely pubescent and green above, white silky-villous and tomentose beneath ; inflorescence small, 3-5 cpi. long, its branches few, short and few-flowered, spreading; sepals about 1 mm. long, ovate, villous; petals broadly obovate or oval, a little exceeding the sepals, stamens 20, about 1.5 mm. long.
Type locality : Alta, Wahsatch Mountains, Utah.
Distribution : Mountains of Colorado, Wyoming, and Utah ; apparently also in California.

Sericotheca franciscana Rydberg, sp. nov
spiraea discolor Brew. & Wats. Bot. Calif. 1 : 170, in part. 1876. Not Spiraea discolor Pursh.
Schizonoius ariaefolius Greene, Fl. Fran. 58 ; in part. 1891.
Holodiscus ariaefolius Greene, Man. Bay Reg. 113 ; in part. 1894.
Holodiscus discolor ariaefolius Jepson, Fl. W. Middle Calif. 277, in part. 1901.
A tall shrub, 2-7 m. high; bark of the young twigs rather dark-brown, villous and tomentose, that of the older branches more or less exfoliating ; petioles 5-10 mm. long, villous ; leaf-blades thick, 3-6 cm. long, rounded-ovate, acute at the apex, rounded or truncate at the base, rarely somewhat cuneate, not decurrent, dark-green and densely pubescent (when young almost velvety) above, white villous and tomentose beneath, usually double-toothed with ovate, mucronate teeth ; inflorescence conic or ovate, 5-15 cm. long, 5-10 cm. wide, twice or thrice compound, with divergent villous branches ; bracts linear ; hypanthium small, saucer-shaped; sepals ovate, acute, nearly 1.5 mm. long, thick; petals oval, white. over 1,5 mm. long ; stamens about 20 ; filaments about 2 mm. long; pistils and fruit as in the preceding.
Type collected at San Iveandro, California, in 1888, L. M. Underwood (herb. N. Y. Bot. Gard.). DiSTtiiBUTiON : Hills and mountains of Oregon and California, near the coast, from Columbia River to San Luis Obispo.