408 ROSACEAE 



Fruit of 1-5 dehiscent follicles. 



Carpels alternate with the sepals or fewer in number; stipules none or deciduous. (Spiraeeae) 



Leaves opposite; tree. 1- Lyonothamnus. 



Leaves alternate; herbs or shrubs. 



Carpels 1-5, when more than 1, united below; endosperm present. 2. Physocarpus. 



Carpels usually 5, distinct; endosperm none. 



Flowers perfect; leaves simple; plants more or less woody. 

 Leaves entire or toothed; filaments distinct. 



Leaves deciduous; carpels dehiscent on the ventral suture. 3. Spiraea. 



Leaves persistent; carpels dehiscent on both sutures. 4. Petrophytum. 



Leaves twice or thrice 3-cleft; filaments united at base. 5. Luetkea. 



Flowers dioecious; leaves twice or thrice compound; tall herbs. 6. Aruncus. 



Carpels opposite the sepals; stipules present and persistent; leaves pinnately dissected. {Sorbarieae) 



7. Chamaebatiaria. 

 Fruit of indehiscent achenes or drupelets. 



Carpels not enclosed by a fleshy hypanthium. 



Carpels becoming dry achenes (inserted on a fleshy colored receptacle in Fragaria). 



Ovaries 2-ovuled, the ovules one above the other; achenes usually 1-seeded and arranged in a 

 single circle. 

 Shrubs with simple leaves; hypanthium hemispheric. (Holodisceae) 8. Holodiscus. 

 Perennial herbs, with pinnately dissected leaves. (Ulmarieae) 9. Filipendula. 



Ovaries 1-ovuled; achenes if many, spirally arranged. 



Leaves and branches alternate; disk at the mouth of the hypanthium annular or wanting. 

 Styles articulate with the ovary and deciduous. (Potentilleae) 

 Stamens numerous, rarely 5 in Ivesia. 

 Receptacle not enlarged in fruit. 



Stamens inserted on the hypanthium some distance above the receptacle, 

 without an annular thickening at the base of the filaments; petals 

 usually white, rarely pale yellow. 

 Stamens 10 or 20; filaments dilated. 10. Horkelia. 



Stamens 5-20; filaments filiform. 11. Ivesia. 



Stamens inserted very near the base of the receptacle on a more or less 

 evident annular thickening; petals yellow, rarely white. 



12. Potentilla. 

 Receptacle enlarged in fruit and becoming spongy or fleshy and red; style lateral; 

 ovules ascending, amphitropous; leaves trifoliolate. 

 Petals yellow; receptacle spongy. 13. Duchesnea. 



Petals white; receptacle juicy. 14. Fragaria. 



Stamens 5; leaves trifoliolate. 15. Sibbaldia. 



Styles not articulate with the ovary, persistent. 



Ovules anatropous or amphitropous, inserted at the point where the style arises, 

 pendulous or when the style is subbasal, ascending; radicle superior. 

 Herbs; petals none except in Agrimonia. (Sanguisorbieae) 

 Hypanthium not prickly. 



Flowers minute, cymosely clustered; hypanthium bracteolate, urceolate, 



loosely investing the achenes in fruit. 16. Alchemilla. 



Flowers spicate or capitate; hypanthium not bracteolate, 4-angled, in- 

 durate in fruit; sepals petaloid. 17. Sanguisorba. 

 Hypanthium prickly. 



Prickles on the hypanthium barbed; petals none. 18. Acaena. 



Prickles on the hypanthium hooked; petals present. 



19. Agrimonia. 

 Shrubs with minute simple leaves and paniculate flowers; style doubly bent. 

 (Adenostomateae) 20. Adenostoma. 



Ovules orthotropous, inserted at the base of the ovary; radicle inferior. 

 Hypanthium hemispheric to turbinate, persistent. (Dryadeae) 

 Pistils several to many. 



Leaves simple, entire or crenate; flowers 8-10-merous; depressed under- 



shrubs. 21. Dryas. 



Leaves compound, except in Cowania; flowers 5-merous. 

 Perennial herbs; sepals valvate; leaves pinnate. 



Style conspicuously bent and geniculate above, upper portion 



usually hairy and readily deciduous. 22. Geum. 

 Style neither conspicuously bent nor geniculate, upper portion 

 glabrous, persistent or tardily deciduous. 



23. Sieversia. 

 Shrubs; sepals imbricate; leaves small, pinnatifid. 



Bractlets present; pistils numerous. 24. Fallugia. 



Bractlets absent; pistils few. 25. Cowania. 



Pistil usually solitary; shrubs. 



Leaves small, 3-lobed; sepals imbricate. 26. Purshia. 



Leaves thrice pinnatifid; sepals valvate. 27. Chamaebatia. 



Hypanthium salverform, the tube cylindric, persistent, the limb saucer-shaped, 

 deciduous. (Cercocarpeac) 28. Cercocarpus. 



Leaves and branches opposite; disk at the mouth of the hypanthium forming a cylindric tube 

 separating the stamens from the pistils; shrubs. (Coleogyncae) 



29. Coleogyne. 



Carpels becoming drupelets, few to many; ovules 2, collateral; stamens few to many, inserted on the 

 margin of the flat or saucer-shaped hypanthium; plants often prickly. (Rnbeac) 



6 30. Rubus. 



Carpels enclosed in the hypanthium, which becomes fleshy and usually colored in fruit. (Roseae) 



