VOL. II.] 



CROWFOOT FAMILY. 



Petals small, shorter than or equalling the sepals. 

 Styles very short. 



Basal leaves cordate ; plant glabrous or nearly so. 15. R. abortivus. 

 Basal leaves not cordate ; plant villous. 16. R. micranthus. 



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



17. R. Alleghaniensis. 

 Leaves all lobed or divided. 



Plant glabrous; stem hollow; flowers very small. 18. R. sceleralus. 



Plants more or less pubescent. 



Beak of the achene strongly hooked; flowers 4" -5" wide. 19. R. recurvatus. 

 Beak of the achene short. 



Erect plants, naturalized in fields; flowers i' broad. 



Calyx spreading; roots fibrous. 20. R. acris. 



Calyx reflexed; stem bulbous-thickened at base. 21. R. bulbosus. 

 Erect or ascending plants of moist soil; flowers 3" -6" broad. 



Petals not longer than the reflexed sepals. 22. R. Pennsylvanicus 



Petals longer than the sepals. 23. R. Macounii. 



Ascending and creeping by stolons; flowers i' broad. 24. R. repens. 

 Beak of the achene long, stout or slender; flowers 6"-i8" broad. 



Roots slender; beak stout; leaflets cuneate at base. 25. R. septentrionalis. 

 Roots thickened; beak of achene slender, subulate. 



Leaf-segments broad, oblong or obovate. 26. R. hispidus. 



Leaf-segments narrow, linear-oblong. 27. R.fascicularis. 



2. Achenes with a few scattered papillae near the margins. 28. R. f>arvtilus. 



3. Achenes rough-papillose all over. 29. R. parviflorus. 



4. Achenes muricate or spiny. 



Leaf-lobes broad, obtuse. 30. R. muricatus. 



Leaf -lobes narrow, subacute. 31. R. arvensis. 



i. Ranunculus delphinifolius Torr. 

 Yellow Water- Crowfoot. (Fig. 1595.) 



Ranunculus multifidus Pursh, Fl. Am. Sept. 736. 



1814. Not Forsk. 1775. 



R. delphinifolius Torr. ; Eaton, Man. Ed. 2, 395. 1818. 

 Ranunculus lacustris Beck & Tracy, N. Y. Med. and 



Phys. Journ. 2: 112. 1823. 



Aquatic or partly emersed, branching, some- 

 times several feet long. Immersed leaves re- 

 peatedly divided into capillary segments, short- 

 petioled, i'-3' long; emersed leaves glabrous or 

 pubescent, ^ / -2 / broad, petioled or the upper 

 nearly sessile, 3-5 divided, the divisions cleft into 

 linear or cuneate segments; flowers yellow, <)"- 

 18" broad; petals 5-8, much longer than the 

 sepals; head of fruit globose or oblong, 3 // -5 // 

 long; achenes less than \" long, callous-mar- 

 gined, tipped with a straight persistent beak of 

 one-half their length or more. 



In ponds, Ontario to Michigan, south to North 

 Carolina and Missouri. The so-called var. terresrist 

 appears to be an emersed form. June-Aug. 



2. Ranunculus Purshii Richards. 



Pursh's Buttercup. 



Ranunculus Purshii Richards. Frank. Journ. 741. 1823. 

 Ranunculus limosus Nutt. ; T. & G. Fl. N. A. i: 20. 



1838. 

 Ranunculus multifidus var. repens S. Wats. Bot. 



King's Exp. 8. 1871. 



Perennial, creeping, pubescent at least on the 

 younger parts, sometimes densely so; stems slender, 

 often rooting from the lower nodes, a'-S' long. 

 Leaves slender-petioled, orbicular or reniform in 

 outline, %'-\' wide, palmately divided nearly to 

 the base into obtuse lobes or segments; flowers yel- 

 low, long-peduncled, 2 // -7 // broad; sepals spread- 

 ing, ovate, obtusish, early deciduous; petals about 

 5; head of fruit subglobose or ovoid-oblong, obtuse, 

 2 // -3 // long; achenes little compressed, smooth, ]^ f 

 long, acutish on the back, abruptly tipped with a 

 slender style of about one-third their length. 



In moist soil, northern Michigan and Minnesota to 

 western Ontario and arctic America, west to British 

 Columbia, south in the Rocky Mountains to Colorado 

 and Utah. July-Aug. 



(Fig. 1596.) 



