PaRT 3, 1908] ROSACEAE 263 
over 1.5 mm. long; stamens about 20; filaments about 2 mm. long; pistils and fruit as in 
the preceding. 
Type collected at San Leandro, California, in 1888, L. WM. Underwood (herb. N. Y. Bot. Gard.). 
_ DISTRIBUTION : Hills and mountains of Oregon and California, near the coast, from Columbia 
River to San Luis Obispo. ; 
3. Sericotheca pachydisca Rydberg, sp. nov. 
? Schizonotus argenteus intermedius Kuntze, Rev. Gen. 1: 225. 1891. 
Twigs brown, angled, sparingly villous; petioles 3 mm. long; leaf-blades broadly ovate, 
2-3 cm. long, and nearly as broad, coarsely few-toothed with rounded-ovate mucronulate 
teeth, glabrous above, grayish- or brownish-silky and tomentulose beneath; panicle ovoid, 
1-1.5 dm. long and nearly as broad, twice compound; sepals broadly ovate, tomentose 
without, glabrous within, acute; petals elliptic, 2.5 mm. long; stamens 20, inserted on 
the margin of a prominent disk; filaments subulate. 
Type collected in the Valley of Mexico, at Tacuboya, in 1865 or 1866, Bourgeau 267 (U. S. 
Nat. Herb.). 
4. Sericotheca dumosa (Nutt.) Rydberg. 
Spiraea discolor Torr. Ann. Lyc. N. ¥. 2: 195. 1827. Not Spiraea discolor Pursh, 1814. 
Spiraea ariacfolia discolor T. & G. Fl. N. Am. 1: 416. 1840. 
igi d fae Nutt.; T. & G. Fl. N. Am. Joc. cit., as a synonym. — Hook. London Jour. Bot. 6: 
Spiraea discolor dumosa S. Wats. Bot. Calif. 1: 170. 1876. 
Schizonotus argenteus dumosus Kuntze, Rev. Gen. 226. 1891. 
Holodiscus discolor dumosa Dippel, Handb. Laubh. 3: 508. 1893. 
Schizonotus dumosus Koehne, Deuts. Dendr. 265. 1893. 
Holodiscus dumosus Heller, Cat. N. Am. Pl. 4. 1898. 
Afolodiscus australis Heller, Bull. Torrey Club 25: 194, 1898. 
Schizonolus discolor dumosus Rehder, 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 short- 
hairy 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 vil- 
lous 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. 
ILLUSTRATION : Bull. Torrey Club 25: pl. 338 (as Holodiscus australis), 
5. Sericotheca Boursieri (Carr.) Rydberg. 
Spiraea Boursiert Carr. Rev. Hort. 1859: 520. 1859. 
A shrub, 1 m, high or less, branched from the base; bark of the young twigs light- 
brown, densely villous; that of the older branches dark-gray or brown or nearly black, ex- 
foliating ; 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 
2mm. long; petals oval, a little longer than the sepals; stamens 20, 2 mm. long; pistils 
5; carpels about 2mm. long, their beaks 1 mm. 
TYPE LOCALITY: California. 
DISTRIBUTION: Mountains of California and adjacent Nevada. 
ILLUSTRATION : Rev. Hort. 1859: f. 108. 
6. Sericotheca saxicola (Heller) Rydberg. 
Holodiscus saxicola Heller, Muhlenbergia 1: 41. 1904. 
A shrub, about 1 m. high, much branched; bark of the young twigs light-brown, vil- 
lous; that of the older branches brown or gray, exfoliating ; leaf-blades broadly oval, ovate 
