BUTTERCUP FAMILY 85 
lobed and cleft into oblong or linear divisions. Flowers about 1 in. 
in diameter. Petals 5-7, yellow, spatulate-oblong or obovate. Akenes 
hardly margined, beak slender, straight or slightly curved. On hill- 
sides or in woods or prairies. 
5. R. septentrionalis Poir. Mars Buttercup. Stems smooth or 
slightly hairy, erect, or in wet ground often forming long runners. 
Leaves 3-divided, on long petioles, the divisions stalked, cleft or lobed, 
and wedge-shaped. Petals yellow, obovate, twice as long as the 
sepals. Akenes flat, strongly margined, beak stout and nearly straight. 
In moist soil. 
6. R. hispidus Michx. Reciinrine Butrercur. Perennial. Stems 
ascending or spreading, densely soft-hairy when young, few-leaved. 
Leaves pinnately 3-5-divided, with sharply cleft divisions. Flowers 
4-1} in. in diameter. Petals about twice as long as the spreading 
sepals. Head of fruit globose or nearly so. Akenes broadly oval, 
lens-shaped, with.a narrow margin. In dry woods and thickets. 
7. R. pennsylvanicus L.f. Uprigut BuTTERcup. Perennial. Stems 
rough-hairy, erect, 2-8 ft. high. Leaves compound in threes, on long 
and very hairy petioles; leaflets long-stalked, 3-parted, the divisions 
sharply lobed or toothed. Flowers small. Petals yellow, shorter than 
the sepals. Akenes flat, smooth, in oblong heads; beak broad and 
straight. On low ground.* 
8. R. bulbosus L. Butsous Buttercup, Earty Buttercup. 
Stem upright, from a solid bulb about as large as a filbert, about 
1 ft. high, hairy. Basal leaves 3-divided, the divisions lobed and 
cleft. Peduncles furrowed. Flowers large and showy (4-1 in. in 
diameter). Sepals strongly reflexed. Petals roundish, wedge-shaped 
at the base. Akenes with a very short beak. Naturalized from 
Europe. Common in grass fields in New England. 
9. R. acris L. Tatx Burtercur. Erect, hairy, 2-3 ft. high. 
Leaves 3-7-parted, the divisions of the lower ones wedge-shaped, 
deeply cut and lobed. Peduncles not furrowed. Sepals spreading, 
downy. Petals obovate, a little smaller and paler yellow than in 
No. 8. A common weed, naturalized from Europe, in grass fields 
and elsewhere, especially eastward. 
Il. THALICTRUM L. 
Erect perennial herbs. Leaves compound, with stipules. 
Flowers in panicles or racemes, often somewhat moncecious 
or dicecious, wind-fertilized. Sepals 4-5, petal-like. Petals 
none. Stamens many. Carpels few or many; ovule 1. Fruit 
a small head of akenes. [The following species are both 
usually dicecious. ] 
