518 ROSACEAE 



inserted on the calyx or receptacle, inflexed or incurved in bud; receptacle (hypanthium) often adnate to tlie calyx-tube; carpels 1 

 to many, free or connate, sometimes adnate to the calyx-tube or perigynous receptacle, the ovules solitary or collaterally paired in 



each locule, anatropous; fruit various. About 100 genera, with about 3,000 species, cosmopolitan, especially abundant in 



temperate regions. 



lA. Fruit dehiscent; stipules sometimes absent. 

 2A. Leaves simple, entire or lobed. 



3A. Stipules present; carpels solitary; inflorescence a corymbose panicle 1. Stephanandra 



3B. Stipules absent; carpels 5; inflorescence an umbellate raceme or panicle 2. Spiraea 



2B. Leaves pinnate or ternately compound. 



4A. Shrubs; carpels connate at base, opposite the calyx-lobes; leaves pinnate; stipules present 3. Sorbaria 



4B. Herbs; carpels free, alternate with the calyx-lobes; leaves ternately compound; stipules absent 4. Aruncus 



IB. Fruit indehiscent, dry or fleshy. 



5A. Ovary superior or rarely apparently inferior because of the tightly enclosing calyx -tube. 

 6A. Carpels many, if 1 or 2, not drupelike; leaves usually compound. 

 7A. Carpels not enclosed within a fleshy calyx-tube (hypanthium). 

 8A. Carpels superior, not enveloped when ripe within the calyx-tube. 

 9A. Filaments persistent. 



lOA. Fruitlets (achenes) dry, not fleshy; plants unarmed. 

 11 A. Styles deciduous. 



12A. Shrubs with simple leaves. 



13A. Flowers white, 4-merous, calyculate at base; leaves opposite 5. Rhodotypos 



13B. Flowers usually yellow, 5-merous, not calyculate; leaves alternate 6. Kerria 



12B. Herbs, rarely shrubs; leaves compound. 

 14A. Carpels many. 



1 5A. Receptacles accrescent after anthesis. 



16A. Flowers yellow; receptacles not fleshy 7. Dtichesnea 



16B. Flowers white; receptacles fleshy in fruit 8. Fragaria 



15B. Receptacles scarcely accrescent; herbs, rarely shrubs, with ternately or pinnately, rarely palmately compound 



leaves; flowers yellow, rarely white or blood-red 9. Potentilla 



14B. Carpels few or rather few. 



17A. Herbs; petals prominent; stamens many 10. Waldsteinla 



17B. Dwarf procumbent subshrubs; petals small; stamens 5 11. Sibbaldia 



IIB. Styles persistent, usually elongate after anthesis. 



ISA. Calyx-lobes and petals 8 or 9; leaves simple, evergreen, obtusely toothed; styles plumose in fruit; dwarf shrubs. 



12. Dryas 

 18B. Calyx-lobes and petals 5; leaves pinnately compound; styles sometimes plumose in fruit; dwarf shrubs or herbs. 



13. Geum 

 lOB. Fruitlets juicy in fruit; usually armed plants with prickles or bristles 14. Rubus 



9B. Filaments deciduous after flowering; fruit an achene 15. Filipendula 



8B. Carpels inferior, enveloped by a nonfleshy calyx-tube. 

 19A. Petals absent. 



20A. Leaves pinnately compound; flowers not calyculate 16. Sanguisorba 



20B. Leaves simple, palmately lobed; flowers calyculate at base 17. Alchemilla 



19B. Petals present; calyx with hooked bristles; leaves pinnately compound 18. Agrimonia 



73. Carpels enclosed in a fleshy calyx-tube; usually armed shrubs 19. Rosa 



6B. Carpel solitary; fruit a drupe; trees or large shrubs, usually deciduous, rarely evergreen; leaves simple, usually with a pair of glands 



near the base or on the upper portion of the petioles 20. Prunus 



5B. Ovary inferior; carpels 2-5, connate and adnate to the receptacle; fruit a pome, sometimes berrylike. 



21A. Carpels bony; fruit drupelike 21. Crataegus 



2 IB. Carpels with coriaceous or papyraceous walls at maturity; fruit a 1- to 5-loculed pome, each locule with 1 or more seeds. 

 22A. Evergreen trees; leaves coriaceous, simple, toothed or entire. 



23A. Inflorescence a compound corymb or flat-topped panicle 22. Photinia 



23B. Inflorescence an acute-topped panicle. 



24A. Calyx persistent; fruit rather large, yellow in maturity 23. Eriobotrya 



24B. Calyx deciduous; fruit small, black 24. Rhaphiolepis 



22B. Deciduous trees or shrubs; leaves simple or compound. 



25A. Flowers in umbels or fascicles, rarely in umbellike corymbs or solitary. 



26A. Carpels many-seeded; flowers short-pedicelled 25. Chaenomeles 



26B. Carpels 1- or 2-seeded; flowers on rather elongate pedicels. 



27A. Styles connate at base; fruit usually without or with very few stone-cells in the flesh 26. Malus 



27B. Styles free; fruit with abundant stone-cells 27. Pyrus 



25B. Flowers in racemes or compound-corymbs. 



28A. Flowers in racemes 28. Amelanchier 



28B. Flowers in compound corymbs. 



29A. Fruiting pedicels with prominent warts; leaves coriaceous, finely toothed; calyx persistent 29. Pourthiaea 



29B. Fruiting pedicels without prominent warts; leaves pinnately compound or if simple the calyx deciduous after anthesis. 



30. Sorbus 



