ROSACEAE. 179 



Style lateral ; ovules ascending and amphitropous. 

 Achenes glabrous ; herbs. 



Achenes numerous ; stamens about 20. 



Receptacle neither enlarged in fruit nor becoming pulpy ; leaves 



interruptedly pinnate ; petals yellow. 7. Argentina. 



Receptacle much enlarged in fruit and becoming red and pulpy ; 

 leaves trifoliate ; petals white or pinkish. 8. Fragaria. 

 Achenes 10-15; stamens 5; leaves trifoliate; petals yellowish. 



9. SiBBALDIA. 



Achenes hairy; shrubs with pinnate leaves. ^o. Dasiphoea. 



Styles nearly basal ; ovules ascending or erect, orthotropous. 



Stamens 5; pistils 5-10; bractlets wanting; leaves twice ternate. 



11. Chamaerhodos. 

 Stamens and pistils numerous ; bractlets present ; leaves pinnate. 



12. Drymocallis. 

 Style not articulated to the ovary, persistent, at least the lower portion. 



Style geniculated above, the upper hairy portion deciduous ; herbs. 



13. Geum. 

 Style not geniculated above, wholly persistent. 



Petals normally 5 or none. 



Herbs with woody rootstocks and pinnate leaves ; bractlets present ; 



carpels numerous. 14. Sieversia. 



Shrubs or trees. 



Bractlets present ; carpels numerous with plumose styles. 

 ■* 15. Fallugia. 



Bractlets wanting ; carpels solitary or few. 



Hypanthium saucer-shaped or hemispherical ; carpels 5 ; flowers 



panicled. 16. Holodiscus. 



Hypanthium funnel-form or tubular ; carpels solitary ; flowers 

 solitary. 

 Petals 5 ; style not elongated in fruit ; calyx persistent ; leaves 



3-cIeft. 17. KuNziA. 



Petals wanting ; style elongated and plumose in fruit ; calyx 

 deciduous from the hypanthium ; leaves toothed. 



18. Cercocarpus. 

 Petals 8-9 ; dwarf matted undershrubs with solitary flowers and simple, 

 in ours crenate leaves. 19. Dryas. 



Hypanthium constricted at the throat, wholly enclosing the achenes. 



Hypanthium dry, turbinate ; upper portions armed with hooked prickles ; herbs ; 



carpels few ; flowers racemose. 20. Agrimonia. 



Hypanthium in fruit becoming fleshy ; carpels numerous ; shrubs with large 

 flowers solitary or in small corymbs. 21. Rosa. 



I. OPULASTER Medic. Nine-bark. 



Carpels 3-5, united only at the base. 1. O. intermedins. 



Carpels 2, united at least half their length. 



Bracts obovate or spatulate, often foliaceous and more persistent. 



z. O. Ramaleyi. 

 Bracts linear or linear-oblanceolate, membranous and caducous. 



Pedicels and hypanthium almost glabrous. 3. O. glabratus. 



Pedicels, hypanthium and sepals decidedly stellate. 4. O. monogynus. 



1. Opulaster intermedius Rydb. {Physocarpus opulif alius Coulter, in part.) 

 On river banks and hillsides from 111. and S. D. to Mo. and Colo. — Alt. 

 4000-7000 ft. — Pike's Peak; North Cheyenne Caiion; Colorado Springs; 

 Lower Boulder Caiion. 



2. Opulaster Ramaleyi Aven Nelson. (O. bracteatus Rydb.) In the foot- 

 hills of Colo. — Alt. 5000-6000 ft. — New Windsor; Buckthorn Creek, Larimer 

 Co. ; Cheyenne Caiion ; foot-hills west of Ft. Collins. 



