402 ROSACEAE 



Carpels 2, united half theii length, or only 1 . 



Carpels usually 2; stamens similar or nearly so. 



Mature carpels more or less turgid; styles more or less spreading. 



Bracts obovate or spatulate, often foliaceous and more or less persistent. 



4. O. bracteatus. 

 Bracts linear or linear-oblanceolate, membranous and caducous. 



Pedicels and the hypanthium almost glabrous; sepals stellate only on the 

 inner surface and near tlie margin; shrub 1 m. high or more. 



5. O. glabratus. 

 Pedicels, hypanthium and calyx densely stellate; shrub 0.5 m. high or less. 



Leaves green on both sides, almost glabrous. 6. O. monogynus. 



Leaves paler and densely stellate beneath. 7. O. Hapemanii. 



Mattire carpels flattened and decidedly keeled; styles erect. 8. O. malvaceus. 

 Carpels usually solitary; every other filament longer and with more dilated base; 

 leaves small, finely stellate. 9. O. altcrnans. 



1. O. capitatus (Pursh) Kuntze. Shrub, with surculose branches, some- 

 times even 7 m. high; branches glabrous or shghtly stellate; leaf-blades broadly 

 rounded-ovate or pentagonal in outline, distinctly 3-5-lobed, with incised or 

 doubly serrate lobes, sparingly pubescent or glabrous above, stellate-pubescent 

 beneath, 3-10 cm. long and usually fully as broad ; sepals ovate-acute, stellate; 

 petals orbicular, about 4 mm. long; carpels 8-10 mm. long, ovate, rather long- 

 acuminate. Spiraea capitata Pursh. Woods: B.C. — Ida. — Calif. Subtnont. 

 My-Jl. 



2. O. cordatus Rydb. Tall shrub; branches brown, glabrous and shining; 

 leaf-blades rounded-cordate to somewhat reniform in outline, 4-10 cm. long and 

 about as broad, 3-5-lobed, with rounded or acute lobes, serrate, with rounded- 

 ovate teeth, glabrous on both sides or with scattered hairs beneath; inflorescence 

 dense; sepals ovate, acute, densely stellate, 3-4 mm. long; carpels 8-9 mm. long, 

 abruptly acute. Open woods: w Ida. — -n Calif. Suhmont. Je-Jl. 



3. O. intermedius Rydb. Shrub 1-1.5 m. high; branches glabrous or 

 nearly so; blades ovate to orbicular in outline, usually shallowly 3-lobed, 2-6 cm. 

 long, doubly crenate, glabrous or nearly so above, usually sparingly hairy be- 

 neath; inflorescence dense; bracts linear-oblanceolate, caducous; sepals ovate, 

 acute, densely stellate on both sides; petals 4 mm. long; carpels united at the 

 base, rounded-eUipsoid, abruptly acuminate, 7-8 mm. long. O. Ramaleyi A. 

 Nels., mainly. P. intermedius C. K. Schneider. Creek banks and hillsides: 

 w N.Y.— Mo.— Colo.— S.D. Plain— Suhmont. Je-Jl. 



4. O. bracteatus Rydb. Shrub 1-2 m. high; branches yellowish green, 

 glabrous; leaf -blades 2-7 cm. long, broadly ovate or subcordate in outhne, more 

 or less deeply 3-lobed, doubly crenate, glabrous or nearly so, somewhat paler 

 beneath; corymb many-flowered; sepals ovate, acute, densely stellate on both 

 sides, about 3 mm. long; petals 4-5 mm. long; carpels densely stellate, united 

 at least half their length. O. Ramaleyi A. Nels., in part. P. Ramaleyi A. Nels. 

 Mountains: Colo. Sub?7iont. Je-Jl. 



5. O. glabratus Rydb. Shrub about 1 m. high; leaf -blades rounded-ovate, 

 orbicular or sometimes slightly reniform, 2-3 cm. long, glabrous, slightly paler 

 beneath, 3-5-lobed, doubly crenate; sepals oval or rounded-ovate, obtuse, about 

 3 mm. long; petals about 4 mm. long, pink or white; follicles 2, denselj' stellate. 

 Moim tains: Colo. Suhmont.— Mont. Je-Jl. 



6. O. monogynus (Torr.) Kuntze. Shrub usually less than 1 m. high, with 

 usually decumbent stems; blades 1-3 cm., rounded-ovate to reniform in outline, 

 usually rather deeply t>-5-lobed, incised; sepals lance-ovate to elliptic, usually 

 obtuse; petals about 3 mm. long; follicles densely stellate, 3-4 mm. long, with 

 ascending-spreading beaks. P. Torreyi Maxim. P. monogynus Coult. Moun- 

 tains: (Black Hills) S.D.— Wyo.— N.M.— Nev. Suhmont.— Mont. My-Jl. 



7. O. Hapemanii Rydb. Low shrub, 1 m. or less high; blades rounded- 

 ovate to reniform in outline, 1-2 cm. broad, rather deeply 3-lobed, incised, obtuse 

 or rounded at the apex, stellate on both sides, paler beneath; sepals broadly 

 ovate, obtuse, about 3 mm. long; petals about 3 mm. long; foUicles 2, densely 

 stellate; beaks ascending-spreading. Mountains: Wyo. — Utah. Mont. Je-JI. 



8. O. malvaceus (Greene) Kuntze. Shrub 1-2 m. high; leaf-blades orbicu- 

 lar or rounded-ovate in outUne, more or less distinctly 3-5-lobed, doubly crenate, 



