EOSACEAE (rose FAMILY) 455 



* Mature carpels papery or soft-cartllaglnous, 

 4- Cella of the compound ovary as many as the styles, without false or pai-tial partitions, 



6. PyxUS. Fruit depressed -globose to ellipsoidal or obovoid ; its carpels enveloped in the fleshy 



receptacle, papery or Boft-cartilaginous, usually 2-ovuled and 2-seeded. Leaves simple or 

 compound. 

 ♦- -I- Cells of the compound ovary subdivided by partial partitions projecting Inward from the back. 



7. Amelanchier. Carpels usually 6. Leaves simple. Unkrmed. 



* * Mature carpels very hard and bony, distinct or firmly coherent in the fleshy fruit. 



8. Crataegus. Ovules in each cell either solitary or If 2 unequal, one sessilo and fertile, the 



other stalked and sterile. Shrubs and small trees, usually armed. Leaves simple, mostly 

 serrate or dentate, thin or coriaceous, 



9. Cotoneaster. Ovules 2 in each cell, equal. Armed shrub with coriaceous oval crenulate 



evergreen leaves. 



rribe in. POTEKTfLLEAE. Carpels few-many, l(-2)-ovuled, becoming dry achenes, not In 

 closed at maturity. Chiefly herbs. 



* Styles not elongated after anthesis, mostly deciduous. 

 ■I- Eeceptacle pulpy and much enlarged In fruit. 



10. Fragaria. Petals white. Leaves 8-foliate. Bractlets alternating with the calyx-lobes. Ee- 



ceptacle Juicy. 



11. Duchesnea. Petals yellow. Eeceptacle spongy, not juicy. 



+- •*- Eeceptacle dry or nearly so, not greatly enlarged lu fruit. 

 ++ Stamens 5. 



12. Sibbaldia. Stamens alternate with the petals. Leaflets mostly 3-toothed at the end. 



13. ChamaerhOdOS. Stamens opposite the petals. Leaflets cleft into linear segments. 



■H- ++ Stamens numerous. 

 — Carpels 1-ovuled. 



14. Waldsteinia. Achenes few, 2-6, rarely 10. 



15. Potentilla. Achenes numerous. Petals 5 (rarely 4), conspicaons. Calyx-lobes as many, 



with an alternating set of bractlets. 



=- — Carpels 2-ovuled. 

 18. Filipecdula. Leaves pinnate ; stipules kidney-formed. 



* * Styles persistent and elongating after anthesis, often plumose or jointed, 



17. Geum. Calyx-lobes usually with 5 alternating small bractlets. Stamens and carpels numer- 



ous ; styles becoming plumose or hairy tails, or naked and straight or jointed. 



Tribe IV. RUBEAE. Pistils several or numerous, becoming drupelets in fruit. Ovules 2 and 

 pendulous, but seed solitary. Perennials, herbaceous or with biennial soft-woody steins. 



18. RubuS. Pistils mostly numerous, fleshy in fruit, crowded upon a spongy receptacle. 



19. Dalibarda. Plstfls 5-10, in the bottom of the calyx, nearly dry in fruit. 



Tribe V. POTERIeAE. Pistils 1-4, becoming achenes, completely inclosed in tUe dry and Ann 

 calyx-tube, which Is constricted or nearly closed at the throat. Herbs with compound or lobed 

 leaves. Petals often none. 



20. Alchemilla. Calyx nrceolate, bracteolate. Petals none. Stamens 1-4. Flowers minute, 



clustered. 



21. Agrimonia. Calyx top-shaped or bell-shaped, with a margin of hooked prickles. Stamens 



5-12. Flowers yellow. In long racemes. 



22. Sanguisorba. Calyx-lobes petaloid ; tube 4-flngled, naked. Petals none. Flowers densely 



capitate or spicate. 



Tribe VI. r6SEAE. Pistils many, becoming bony achenes. Inclosed in the globose or urn-shaped 

 fleshy calyx-tube, which resembles a pome. Petals conspicuous. Stamens numerous. 



23. Rosa. The only genus. Prickly shrubs with pinnate leaves. 



Tribe VII. PRtlNEAE. Ovary superior and not Inclospd in the calyx-tube at maturity. Calyx 

 deciduous, without bractlets. Pistil, solitary, becoming a stone-fruit. Ovules 2, but seec 

 almost always solitary. Style terminal. Trees or shrubs, with simple mostly serrate leaves, 

 :i4. Prunus. Flo wcis perfect. Petals and calyx -lobes 5. Stone of the drupe bony, 



