248 ROSACEAE (ROSE FAMILY) 



1. Physocarpus pubescens (Rydb.) A. Nels. A shrub about 1 m. high, 

 with strict branches and light colored shreddy bark; pubescent with branched 

 or stellate hairs: leaves orbicular with cordate base, slightly 5-lobed and 

 doubly crenate, about 2 cm. long: sepals densely stellate-tomentose, ovate, 

 obtuse: petals broadly obovate, about one third longer than the sepals: ovaries 

 densely stellate-tomentose, united to above the middle; carpels not much 

 inflated, the apex straight or perhaps somewhat spreading in fruit. (Opu- 

 laster pubescens Rydb. Mem. N. Y. Bot. Card. 1: 208. 1900.) Montana to 

 Colorado and Utah. 



2. Physocarpus Ramaleyi A. Nels. Shrubby, 1-2 m. high; the stems 

 brown with fibrous-shreddy bark; young branchlets green, glabrous: leaves 

 broadly ovate or subcordate, some incisely 3-lobed, the margin more or less 

 doubly crenate-dentate, 2-7 cm. long: corymb many-flowered; the slender 

 pedicels each subtended by a conspicuous bract; bracts spatulate or obovate, 

 sometimes toothed or lobed; pubescence on pedicels soft and rather long, 

 somewhat tufted and substellate: calyx short, hoary-tomentose ; sepals ovate, 

 acute, about 3 mm. long: petals slightly exceeding the sepals: anthers dark 

 purple: ovaries four, densely pubescent; carpels elliptic, inflated, more than 

 twice as long as the sepals, about 7 mm. long, nearly distinct, pubescent, usu- 

 ally three maturing (sometimes only two). (Opulaster bracteatus Rydb. Bull. 

 Torr. Bot. Club 31: 558. 1904; O. Ramaleyi A. Nels. Bot. Gaz. 34: 367. 1902.) 

 Canons of the Colorado Rocky Mountains. 



3. Physocarpus intermedius (Rydb.) A. Nels. Shrub 1-2 m. high: leaves 

 orbicular in outline, with rounded lobes, 2-6 cm. long, obtuse or subcordate 

 at base, crenate: pedicels and calyx finely pubescent: ovaries 3 or 4, rarely 2, 

 pubescent, united below: carpels 6-7 mm. long, rounded or obtuse at apex, 

 tipped with a subulate style. Physocarpus opulifolius, in part. (Opulaster 

 intermedius Rydb. Brit. Man. 492. 1901.) From the Mississippi to central 

 Colorado. 



4. Physocarpus monogynus (Torr.) A. Nels. A low shrub, 5-8 dm. high, 

 branching freely: leaves usually glabrate, deltoid-ovate in outline, incisely 

 3-lobed; the lobes nearly equal, with crenate or incised secondary lobes: 

 corymb few-flowered: petals comparatively large, often rose-tinted: carpels 1 

 or 2; if 2, adnate nearly to the summit, somewhat inflated, about equaling 

 the calyx, 1-seeded: seed obovoid. Physocarpus Torreyi. (Spiraea monogyna 

 Torr. Ann. Lye. N. Y. 2: 194. 1827; O. glabratus Rydb. Bull. Torr. Bot. Club 

 31: 559. 1904.) In the mountains of Colorado. 



5. Physocarpus malyaceus (Greene) A. Nels. Shrub 1-2 m. high: leaves 

 digitately 5- veined, orbicular or oval, sometimes 3-lobed above the middle; the 

 secondary lobes crenate: inflorescence stellate-tomentose, few-flowered: calyx 

 large, broadly campanulate, at maturity the lobes connivent over the fruit: 

 carpels 2, connate nearly to the summit, compressed, forming a bifid fruit like 

 that of a Lepidium. (Neillia malvacea Greene, Pitt. 2: 30. 1889; Opulaster 

 pauciflorus Heller, Bull. Torr. Bot. Club 25: 581. 1898.) Western Wyoming 

 to Utah and Oregon. 



7. SPIRAEA L. MEADOWSWEET 



Shrubs with simple alternate exstipulate leaves and perfect flowers in 

 compound corymbs, or in panicles or spikes. The persistent calyx 5-cleft; 

 the 5 petals and numerous stamens inserted together upon it. Carpels 5, 

 distinct, alternate with the calyx-lobes, becoming dry cartilaginous several- 

 seeded follicles. Seeds small, with thin membranous testa. 



Leaves large (5-8 cm. long); flowers white 1. S. lucida. 



Leaves small (2-4 cm. long); flowers rose-color 2. S. densiflora. 



1. Spiraea lucida Dougl. Hook. Fl. Bor. Am. Sept. 1: 172. 1833. Glabrous, 

 the stems usually simple and erect, 4-8 dm. high: leaves small below, larger 

 upward, oval or elliptic-oblong, incisely serrate around the obtuse or acute 

 summit, pale and glaucescent beneath: inflorescence a compound corymb, 



