424 FLORA 



tttt Terrestrial species with some or all the leaves lobed or divided. 

 Calyx conspicuously black-pubescent ; arctic; flowers white or light yellow. 



10. R. nivalis. 

 Calyx glabrous or pubescent ; flowers yellow. 



i. Achenes smooth, neither papillose, muricate nor spiny. 

 Plants low, arctic-alpine ; leaves small, palmately lobed. 



Flowers 4-6 mm. in diameter ; sepals glabrous or slightly hairy. 



11. R. pygmaeus. 

 Flowers about 1 cm. in diameter; sepals densely hairy. 



12. R. Sabini. 

 Plants neither arctic nor alpine. 



Basal leaves, some or all of them, merely crenate. 

 Head of fruit oblong, 2-3 times as long as thick. 



Flowers 4-12 mm. in diameter ; sepals glabrate or slightly hairy. 



13. R. pedatifidus. 

 Flowers 1.5-2 cm. in diameter; sepals densely villous. 



14. R. cardiophyllus. 

 Head of fruit globose or subglobose. 



Petals large, oblong, longer than the sepals. 



Basal leaves oval or ovate, not cordate. 15. R. ova/is. 

 Basal leaves reniform or orbicular, cordate. 



16. R. Harveyi, 

 Petals small, oblong, shorter than or equalling the sepals. 



Styles very short, curved. 



Basal leaves cordate ; plant glabrous or nearly so. 



17. R. abort ivus. 

 Basal leaves not cordate ; plant villous. 



18. R. micranthus. 

 Styles subulate, hooked, nearly one-half as long as the achene. 



19. R. Alleghaniensis. 

 Leaves all lobed or divided. 



Plant glabrous ; stem hollow ; flowers very small. 20. R. sceleratus. 

 Plants more or less pubescent. 



Beak of the achene strongly hooked ; flowers 8-10 mm. wide. 



21. R. recurvatus. 

 Beak of the achene short. 



Erect plants, naturalized in fields ; flowers 25 mm. broad. 

 Calyx spreading ; roots fibrous. 22. R. acris. 

 Calyx reflexed ; stem bulbous-thickened at base. 



23. R. bulbosus. 

 Erect or ascending plants of moist soil ; flowers 6-12 mm. 

 broad. 

 Petals not longer than the reflexed sepals ; head of fruit 

 oblong to cylindric. 24. R. Pennsylvanicus, 



Petals longer than the sepels ; head of fruit spherical- 

 ovoid. 25. R. Macounii. 

 Ascending and creeping by stolons; flowers 2.5 cm. broad. 



26. R. repens. 

 Beak of the achene long, stout or slender; flowers 12-36 mm. 

 broad. 



Beak stout, sword-shaped ; roots slender ; leaflets cuneate at 

 base. 27. R. septentrionalis. 



Beak of achene slender, subulate ; roots thickened. 

 Leaf-segments broad, oblong or obovate. 



28. R. hispidus. 

 Leaf-segments narrow, linear-oblong. 



29. R.fascicu/aris, 



2. Achenes with a few scattered papillae near the margins. 30. R. parvulus. 



3. Achenes rough-papillosed all over. 31. R '. parviflorus. 



4. Achenes muricate or spiny. 



Leaf-lobes broad, obtuse. 32. R. muricatus. 



Leaf-lobes narrow, subacute. 33. R. arvensis. 



1. Ranunculus Purshii Richards. Pursh's Buttercup. (I. F. f. 1596.) 

 Aquatic or creeping, pubescent at least on the younger parts. Leaves slender- 

 petioled, 6-24 nun. wide, palmately divided nearly to the base into obtuse lobes 

 or segments; petals about 5; head of fruit subglobose or ovoid -oblong, 4-6 mm. 

 long. In moist soil, N. S. to Mich., Minn., western Ont. and Arctic Am., west to 

 Br. Col., Colo, and Utah. July-Aug. 



