244 NORTH AMERICAN FLORA [VoLumE 22 
glabrous, slightly paler beneath, 3-5-lobed, doubly crenate, obtuse or rounded at the apex, 
truncate or cordate at the base; corymb rather small; bracts small, lanceolate, caducous ; 
pedicels 1-1.5 cm. long, glabrous; hypanthium 3.5-4 mm. wide, almost glabrous; sepals 
oval or rounded-ovate, obtuse, sparingly stellate without (mostly near the margin) and 
densely so within, about 3 mm. long; petals rounded-ovate, about 4 mm. long, pink or 
white ; follicles 2, united to above the middle, densely stellate ; seeds nearly 2 mm. long, 
pear-shaped, slightly oblique ; caruncle elongate. 
TYPE LOCALITY: West Spanish Peak, Colorado. 
DISTRIBUTION: Mountains of Colorado. 
10. Opulaster monogynus (Torr.) Kuntze, Rev. Gen. 949. 1891. 
Spiraea monogyna Torr. Ann. Lyc. N. ¥.2: 194, 1827. 
Icotorus monianus Raf. Bull. Bot. Seringe 216. 1830. 
Epicostorus montanus Raf. Atl. Jour. 1: 144. 1832. 
Spiraea opulifolia paucifiora T. & G. Fl. N. Am. 1: 414, in part. 1840. 
Spiraea opultifolia parvifiora Porter & Coult. Syn. Fl. Colo. 33. 1874. 
Neillia Torreyi S. Wats. Proc, Am. Acad. 11: 136, 1876. 
Physocarpus Torreyi Maxim, Acta Hort. Petrop. 6: 221. 1879. 
Neillia monogyna Greene, Pittonia 2: 29. 89. 
Physocarpus monogynus Coult. Contr. U.S. Nat. Herb. 2: 104. 1891. 
Ashrub, usually less than 1 m. high, with usually decumbent stems; branches brownish, 
glabrous or sparingly stellate; petioles 1 cm. long or less; leaf-blades 1-3 cm., rounded- 
ovate to reniform in outline, usually rather deeply 3-5-lobed, incised; glabrous or nearly 
so and green on both sides; corymb rather few-flowered ; bracts lanceolate and caducous ; 
pedicels 1-1.5 cm. long, usually sparingly stellate; hypanthium about 3 mm. wide, stellate ; 
sepals lance-ovate to elliptic, usually obtuse, densely stellate on both sides; petals white, 
orbicular, about 3 mm. long; follicles 2 (rarely 3), united to above the middle, densely 
stellate, 3-4 mm. long with ascending-spreading beaks; seeds obliquely pear-shaped, over 
1.5 mm. long. 
TYPE LOCALITY : Rocky Mountains [Colorado]. 
DISTRIBUTION : High mountains, from the Black Hills of South Dakota and Wyoming to Texas 
and New Mexico; also Nevada. 
11. Opulaster Hapemanii Rvdberg, sp. nov. 
A low shrub, 1 m. or less high; branches brownish and rather densely pubescent; peti- 
oles 1 cm. or less long; leaf-blades rounded-ovate to reniform in outline, 1-2 cm. broad, 
rather deeply 3-lobed, incised, obtuse or rounded at the apex, truncate or cordate at the 
base, more or less densely stellate on both sides, paler beneath; corymb few-flowered; bracts 
lanceolate, caducous; pedicels 1-1.5 cm. long, stellate; hypanthium about 3.5 mm. wide, 
densely stellate ; sepals broadly ovate, obtuse, about 3 mm. long; petals white, rounded- 
oval, about 3 mm. long; follicles 2, densely stellate, united to above the middle; beaks 
ascending-spreading ; seeds pear-shaped, nearly 2 mm. long; caruncle small. 
Type collected in the Big Horn Mountains, Wyoming, August, 1892, Dr. H. Hapeman. 
DISTRIBUTION: Mountains of Wyoming and Utah. 
12. Opulaster malvaceus (Greene) Kuntze, Rev. Gen. 949. 1891. 
Spiraea opulifolia y Hook. Fl. Bor. Am. 1: 171. 1832. 
Spiraea opulifolia paucifiora T. & G. Fl. N. Am. 1: 414, in part. 1840. 
Spiraea paucifiora Nutt.; T. & G. Fl. N. Am. 1: 414, asasynonym. 1840. 
Neillia malvacea Greene, Pittonia 2: 30. 1889. 
Physocarpus malvaceus Kuntze, Rev. Gen. 219. 1891. 
Neillia monogyna malvacea M. EB. Jones, Zoe 4: 43, 1893. 
Opulaster paucifiorus Heller, Bull. Torrey Club 25: 581, 626. 1898. 
Opulaster pubescens Rydb. Mem. N. VY. Bot. Gard. 1: 265. 1900. 
Neillia Torreyi Hook. f. Bot. Mag. pl. 7758. 1901. 
Physocarpus pauctfiorus Piper, Fl, Palouse Reg. 94. 1901. 
A shrub, 1-2 m. high; branches brown, stellate or glabrous; petioles 1-2 cm. long; leaf- 
blades orbicular or rounded-ovate in outline, more or less distinctly 3-5-lobed, doubly cre- 
nate, glabrous or more or less stellate on both sides, thin, obtuse, or those of the sterile 
shoots acute at the apex, usually cordate at the base, 2-6 cm. long and about as broad; 
bracts spatulate or cuneate, caducous; pedicels 1-2 cm. long, densely stellate; hypanthium 
