STANDLEY FLOEA OF GLACIER PARK. 341 



6. MYOSURUS L. 



1. Myosunis lepturus (A. Gray) Howell. Mousetail. Plains at east entrance, 

 Umbach. Annual, 3 to 10 cm. high, glabrous; leaves basal, threadlike, 2 to 4 cm. 

 long; stems 1-flowered; sepals 5, spurred at the top, about 2 mm. long; petals greenish 

 yellow, very small; fruit a slender spike of small beaked achenes. 



7. BATRACHIUM S. F. Gray. Water buttercup. 



Perennials, growing in water; stems branched, very leafy; leaves much divided 

 into threadlike lobes; flowers small, solitary; petals 5, white; fruit a head of small 

 wrinkled achenes. 



Petals broadly obovate, 5 to 7 mm. long; stamens numerous 1. B. flaccidum. 



Petals oblong-obovate, 3 to 5 mm. long; stamens 5 to 12 2. B. drouetii. 



1. Batrachium flaccidum (Pers.) Rupr. Snyder Lake and Swiftcurrent Creek. 

 Wash, to Calif., N. C, and Lab.— Stems slender, glabrous; leaves 1.5 to 3 cm. long: 

 achenes finely hairy. 



2. Batrachium drouetii (Schultz) Nyman. Frequent in ponds and pools. Widely 

 distributed in N. Amer., Eur., and Asia.— Plants slender, glabrous; leaves 1 to 2 

 cm. long; head of achenes globose, 4 mm. thick. 



The species of this genus are not well understood, and the differences between 

 them are imperfectly distinguishable. 



8. HALERPESTES Greene. 



1. Halerpestes cymbalaria (Pursh) Greene. Alkali buttercup. Frequent about 

 east entrance in low places on prairie, sometimes in alkaline spots. Alaska to Calif., 

 N. Mex., N. J., and Lab.; also in Mex. and S. Amer. {Ranunculus cymbalaria 

 Pursh.)— Perennial with long slender runners; leaves heart-shaped or kidney-shaped, 

 glabrous, 0.5 to 3 cm. long, mth low rounded teeth; flower stems 2 to 10 cm. long, 

 1 to 7-flowered; petals 3 to 5 mm. long, yellow; fruit heads longer than broad. 



9. RANUNCULUS L. Buttercup. 



Perennials with fleshy-fibrous roots; leaves entire, toothed, or compound; flowers 

 solitary or in cymes; sepals 5; petals 5, yellow; fruit a head of achenes. 



Leaves all entire 1. R. reptans. 



Leaves toothed, lobed, or divided. 



Plants creeping, the stems rooting at the joints, growing on mud or at the edge of 



water 2. R. purshii. 



Plants not creeping and rooting at the joints. 



Lowest leaves compound, divided into 3 or more leaflets. 



Stems glabrous 3. R. oreganus. 



Stems very hairy 4- R- macounii. 



Lowest leaves toothed or lobed but never divided to the base. 

 Achenes with a hooked beak. Stems with long spreading hairs. 



6. R. bongardl. 

 Achenes with a straight beak or none. 

 Achenes finely hairy; lowest leaves with rounded teeth, not lobed. 



6. R. inamoenus. 

 Achenes glabrous; lowest leaves lobed. 



Petals 5 to 6 mm. long V. R. alpeopMlus. 



Petals 8 to 12 mm. long. 

 Head of achenes somewhat oblong, longer than broad . . 8. R. saxicola. 

 Head of achenes globose 9- R- suksdorfii. 



