EOSACEAE (ROSE FAMILY) 455 



* Mature carpels papery or soft-cartilaginous. ' 



•♦- Cells of the compound ovarj' as many as the styles, without false or partial partitions. 



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



leceptacle, papery or soft-cartilaginous, usually 2-ovuled and 2-seeded. Leaves simple or 

 compound. 

 ♦- -t- Cells of the compound ovary subdivided by partial partitions projecting Inward from the back, 



7. Amelanchier. Carpels usually 5. Leaves simple. Unarmed. 



* * 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 sessile 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. 



Tribe III. POTENTIlLEAE. Carpels few-many, l(-2Vovuled, becoming dry achenes, not in- 

 closed at maturity. Chiefly herbs. 



* Styles not elongated after anthesis, mostly deciduous, 

 -i- Receptacle pnlity and much enlarged in fruit. 



10. Fragaria. Petals white. Leaves 3-foliate. Bractlets alternating with the calyx-lobes. Re- 



ceptacle iuic}'. 



11. Duchesnea. Petals yellow. Receptacle spongj', not juicy. 



♦- +- Receptacle dry or nearly so, not greatly enlarged iu fruit. 



•M- Stamens 5. 



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



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



*+ +1- Stamens numerous, 

 -= Carpels 1-ovuled. 



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



15. Potentilla. Achenes numerous. Petals 5 (rarely' 4), conspicuous. Cah'x-Iobes as many, 



with an alternating set of bractlets. 



■^ = Carpels 2-ovuled. 



16. Filipendula. 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 stems. 

 ^^\^j fj^lS. Rubus. PistOs mostly numerous, fleshy in fruit, crowded upon a spongy receptacle, 

 jbr^ 19. Dalibarda. Pistils 5-10, in the bottom of the calyx, nearly dry in fruit. 



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

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

 P^j-Jlat ~ leaves. Petals often none. 



. .y 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 



i'>-\2. Flowers yellow, in long racemes. 



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



capitate or spicate. 



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

 r-.^ '^ 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 inclosed in the calyx-tube at maturity. Calyx 

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

 nlTn<)><t nhvoys solitary. Style terminal. Trees or shrubs, with simple mostly serrate leaves. 

 %**^24. Prunus. Floweis perfect. Peuls and calyx-lobes 5. Stone of the drupe bony. 





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