296 RANUNCULACEAE 



Lobes of the upper stem-leaves elliptical, oval or obovate. 



20. R. Eschscholtzii. 

 Lobes of the upper stem-leaves linear to oblong. 



Stem about 2 dm. high; lateral lobes of the basal leaves 2-3-toothed. 



21. R. Helleri. 



Stem less than 1 dm. high; lateral lobes of the basal leaves 4-5-toothed. 



22. R. vericundus. 

 Plant more or less pubescent. 23. R. ovalis. 



V. DlGITATI. 



One species. 24. R. Jovis. 



VI. TRITERNATI. 



Plant less than 1 dm. high; petals about 5 mm. long; segments of the leaves very short, 



3-5 mm. long: beak recurved. 25. R. Drummondii. 



Plant usually more than 1 dm. high; petals 5-18 mm. long; segments of the leaves 1 cm. 



or more long; beak slender, not recurved. 

 Primary divisions of the basal leaves petiolate; segments linear, somewhat narrowed 



downward; stems usually several-flowered; roots fibrous. 26. R. stenolobus. 

 Primary divisions of the basal leaves sessile; segments narrowly linear, almost fili- 

 form, not narrowed downward; stems 1-2-flowered; roots fleshy-fibrous. 



27. 'R. adoneus. 



VII. PYGMAEI. 



Sepals glabrous or nearly so; lateral lobes of the basal leaves 2-3-toothed. 



28. R. pygmaeus. 

 Sepals copiously pubescent; lateral lobes of the basal leaves 4-5-toothed. 



22. R. verecundus. 



VIII. ABORTIVI. 



Basal leaves, at least some of them, merely crenate. 

 Achenes pubescent; heads oblong to cylindrical. 



Petals present; sepals not petaloid. 13. R. micropetalus. 



Petals wanting; sepals with petaloid margins. 29. R. apetalus. 

 Achenes glabrous, with a minute beak; heads subglobose. 



Basal leaf-blades cordate at the base; plant glabrous. 30. -R. abortivus. 

 Basal leaf-blades rarely cordate at the base; plant, especially the stem, with 



spreading hairs. 31. R. micranthus. 



All the leaves divided or lobed; annuals. 32. R. sceleratus. 



IX. RECURVATI. 



Flowers small; petals only 2-5 mm. long; basal leaf-blades divided into 3 rhombic or 



cuneate-obovate, cleft divisions. 

 Petals 2-3 mm. long. 



Stem glabrous; achenes glabrous. 33. R. Douglasii. 



Stem hairy; achenes usually hirsute when young. 34. R. Bongardi. 



Petals 4-5 mm. long; achenes glabrous. 35. R. Earlei. 



Flowers larger; petals 5-12 mm. long; basal leaves often biternately cleft into linear, 



lanceolate, ovate, or cuneate divisions; achenes glabrous. 



Pubescence of the stem appressed. 36. R. acriformis. 



Pubescence of the stem spreading. 



Stem low and slender, seldom more than 3 dm. high; petals oblong to oval. 



37. R. occidentalis. 

 Stem tall, 5-10 dm. high; petals broadly obovate. 38. R. montanensis. 



X. REPENTES. 

 Petals less than 1 cm. long. 



Plant glabrous or nearly so. 39. R. oreganus. 



Plant decidedly pubescent. 



Heads of achenes decidedly oblong, about 5 mm. thick. 40. R. pennsylvanicus. 

 Heads of achenes globose, 7-12 mm. thick. 



Plants not stoloniferous ; primary segments of the leaves cuneate at the base; 



beak half as long as 'the body of the achene. 41. R. Macounii. 



Plant producing long lateral branches, rooting at the nodes; primary segments 

 of the lower leaves more or less truncate or subcordate at the base; beak 

 one-third as long as the body of the achene. 42. R. rivularis. 



Petals more than 1 cm. long; stem creeping. 43. R. repens. 



XI. ACRES. 

 One species. 44. R. acris. 



XII. HISPID:. 



Petals obovate: divisions of the leaves lanceolate or ovate. 45. R. platyphyllus. 



Petals elliptic; divisions at least of the upper leaves linear. 46. R. orthorhynchus. 



XIII. MULTIFIDI. 



Leaves deeply cordate at the base, their primary divisions lobed or dissected; style about 



two-thirds as long as the achene. 



Achenes callous-margined. 47. R. delphinifolius. 



Achenes marginless. 



Stem glabrous. 48. R. Purshii. 



Stem pubescent. 49. R. limosus. 



