ROSACE^E. (ROSE FAMILY.) 75 



M- Calyx persistent in fruit : stamens perigynous : carpels several-seeded. 



2. Spiraea. Carpels cartilaginous, 1-valved, distinct. Flowers perfect, rarely polyga- 



mous. Leaves simple, serrate or incised. 



H- -H- Calyx marcescent in fruit : stamens hypogynous : carpels few-seeded. 



3. Aruncus. Carpels cartilaginous, 1-valved, distinct. Flowers dioacious. Leaves re- 



peatedly ternately divided. 



i- >- Seeds with shining stony testa : albumen very distinct : stipules membranaceous, 



caducous. 



4. Physocarpus. Follicles membranaceous, inflated, 2-valved, distinct, often stipitate. 



Flowers perfect, corymbose. Leaves lobed. 



* * Carpels opposite to the calyx-lobes when of the same number. 



5. Chamaebatiaria. Follicles coriaceous, 1-valved, connate at base, several-seeded. 



Albumen distinct. Flowers perfect Leaves small, coriaceous, stipulate, bipinnately 

 dissected. 



* * * Carpel becoming an akene. 



6. Holodiscus. Carpels alternate with the calyx-lobes, with densely silky styles and 2 



collateral pendulous ovules. Akenes membranous, woolly, 1-seeded. Leaves lobed, 

 without stipules. 



Tribe II. RUBE^I. Carpels several or numerous on a spongy receptacle, becoming 

 drupelets in fruit. Calyx open, without bractlets. Stamens numerous. Ovules 2 

 and pendulous, but seed solitary. 



7. Rubus. Carpels indefinitely numerous, berry-like in fruit. Perennial herbs or soft- 



woody shrubs with biennial stems. 



Tribe III. POTENTII^E^E. Carpels numerous, several, or solitary, 1-ovuled, be- 

 coming dry akenes. Calyx not enclosing or at least not constricted over the fruit. 

 Seed erect or ascending. 



* Shrubs: carpels mostly solitary : style not elongated in fruit: stigma decurrent: calyx 



imbricated, without bractlets. Flowers solitary in ours. 



8. Purshia. Petals 5. Leaves 3-cleft. Radicle inferior. 



9. Coleogyne. Calyx 4-parted, colored. Petals none. Leaves opposite, small, narrow, 



entire. Radicle, superior. 



* * Trees or shrubs : carpels solitary or numerous : styles elongated and plumose in fruit : 



calyx imbricated, without bractlets (except in Fallugia) : seed erect. 



10. Cercocarpus. Flowers solitary, axillary, small. Petals none. Carpels solitary, 



rarely 2. Calyx-tube long-cylindrical ; the limb deciduous. Leaves simple, entire or 

 toothed. 



11. Cowania. Flowers solitary, short-peduncled, terminal, showy. Petals 5. Carpels 



5 to 12. Calyx short and turbinate. Leaves cuneate, lobed. 



12. Fallugia. Flowers somewhat panicled, on long peduncles, showy. Petals 5. Carpels 



numerous. Calyx turbinate. Leaves with linear lobes. 



* * * Herbs : carpels few to many : calyx concave or campanulate, valvate in the bud, 



bracteolate. 

 i- Seed erect from the base of the cell : radicle inferior : style strictly terminal, persistent. 



13. Dryas. Like Geum, but petals 8 or 9. 



14. Geum. Carpels very numerous on a dry receptacle : the elongated style in fruit mostly 



geniculate or plumose. Petals 5. 



*- -t- Seed suspended or ascending : radicle superior : style small, naked, not geniculate. 



15. Fragaria. Carpels very numerous, in fruit on a large fleshy scarlet receptacle. Styles 



lateral. Leaves 3-foliolate. 



16. Potentilla. Petals yellow, rarely white, sessile. Stamens usually 20 or more ; fila- 



ments narrow or filiform. Carpels mostly numerous, on a dry receptacle. Leaves 

 pinnate or digitate ; leaflets toothed or cleft, not confluent. 



17. Sibbaldia. Petals yellow, sessile, minute and narrow. Stamens 5 ; filaments very 



short, filiform. Carpels 5 to 10, on a dry receptacle. Leaves 3-foliolate ; leaflets 

 3-toothed. 



