420 The Ohio Naturalist. [Vol. XV, No. 3, 



III. Carpels enclosed in the persistent hypanthium; achenes numerous 

 to one. 



a. Achenes numerous, enclosed in a fleshy hvpanthium. 



17. Rosa. (17). 



b. Achenes 1-2, enclosed in the dry hypanthium. 



18. Agrimonia. (18). 



19. Sanguisorba. (19). 



20. Poterium. 20). 



Genus Key. 



1. Carpels not enclosed in the hypanthium. 2. 



1. Carpels enclosed in the hypanthium. 17. 



2. Carpels numerous, ripening into 1-2-seeded achenes or drupelets, 3. 



2. Carpels usually not more than 10. 11. 



3. Plants woody, usually prickly, or, if not, with shreddy bark. 4. 



3. Plants herbaceous, rarely slightly woody at the base. 5. 



4. Flowers white or rose; shrubs usually prickly: fruit an aggregate of 



drupelets. Rubiis. (9). 



4. Flowers yellow; not prickly or bristly; bark shreddy, achenes pubescent. 



Dasiphora. (2). 



5. Leaves trifoliate; flowers corymbose on a scape. 6. 



5. Leaves pinnate or lobed or, if trifoliate, then the flowers solitary in the 



axils or cymose at the end of leafy branches. 7. 



6. Flowers yellow; achenes on dry receptacles. Waldsteinia. (7). 



6. Flowers white; achenes on fleshy edible receptacles. Fragaria. 



7. Style terminal or nearly so; achenes glabrous or pubescent. 8. 



7. Style lateral or nearly basal; achene glabrous. 9. 



8. Seed erect; style persistent, jointed near the tip, becoming hooked. 



Geum. (1). 



8. Seed pendulous; style deciduous, articulated with the ovulary, not 



becoming hooked. Potentilla. (3)- 



9. Flowers red or purple. Comarum. (.5). 

 9. Flowers yellow or white. 10. 



10. Flowers white; style nearly basal. DrymocaUis. (6). 



10. Flowers yellow; style lateral; plant silvery pubescent. Argentina. (4). 



11. Leaves entire or only slightly lobed. 15. 



11. Leaves compound or deeply palmately lobed. 12. 



12. vShrubs with odd pinnate leaves, stipules small. Schizonotus. (11). 



12. Erect perennial herbs. 13. 



13. Leaves 2-3 times pinnate; stipules minute or wanting. Arimcus. (15). 



13. Leaves palmately lobed, 3-foliate or simply pinnate; stipules large. 14. 



14. Leaves .3-parted or 3-foliate; flowers in loose terminal panicles; follicles 



dehiscent along both sides. Porteranthiis. (10). 



14. Leaves pinnately .3-9-lobed or foliate; flowers in dense cymose panicles; 



follicle-like fruit indehisccnt. Filipendula. (12). 



15. Low herbs with orbicular, cordate leaves; hypanthium zygomorphic 



enclosing the carpels; with normal and clcistogamous flowers. 

 Dalibarda. (16). 



15. Siirubs; leaves ovate orbicular, ovate or lanceolate; hypanthium 



enclosing the carpels. 16. 



16. Leaves somewhat 3-lobed; follicles dehiscent along both .sutures; 



carpels united below. Opidaster. (13). 



16. Leaves entire; follicles dehiscent along one suture, carpels distinct. 



Spiraea. (14). 



17. Shrubs; stems usually prickly; carpels enclosed in the fleshy 



hypanthium. Rosa. (17). 

 17. Herbs; stems not prickly; carpels enclosed in a dry hypanthium. 18. 



