RANUNCULACEiE. 39 



THALICTRUM, L. (Meadow Rue.) Xo involucre. Calyx usually 

 colored. Sepals 4-5 or 7, concave, falling early. Xo corolla. Fila- 

 ments generally enlarged above and longer than the calyx, numerous. 

 Flowers in panicles, dioecious, or polygamous. Ovaries many. Akenes 

 usually sessile, occasionally stipulate, rihbed or swollen, pointed with 

 the short style. Leaves usually ternately compound. Leaflets stalked. 

 Perennial herbs. 



1. T. clavatum, DC. Stem 2 to 3 feet high, smooth. Leaves hiternate, on 

 petioles an inch long ; leaflets roundish, obtusely 3-5-lobed, glaucous beneath. 

 Flowers in loose panicles. Fruit swollen, obovate, striate, acute, and as long 

 as the stipe. June. 



Geography. — Southern Virginia and North Carolina. 



2. T. dioicum, L. (Meadow Rue.) Stem smooth, pale-green, or bluish, 1 to 2 

 feet high, slender. Leaves ternately decompound, on short general petioles. 

 Leaflets roundish, obtusely 3-5-7 lobed, paler beneath. Flowers purplish or 

 pale-green, filaments threadlike, longer than the calyx ; anthers linear, yel- 

 lowish, mucrouate. Sepals 5, obtuse. Inflorescence a panicle. Fruit strongly 

 ribbed and pointed. May. 



Geography.— British. America to Georgia and Alabama. In hilly, rocky 

 woods. 



3. T. polygamum, xMuhl. (T. Cornuti, Gray). (Tall Meadow Rue.) Stem 

 3 to 5 feet high, branching, smooth, or slightly pubescent. Leaves varialile in 

 form, dark-green above and paler beneath, smooth or pubescent; stem leaves 

 without general petioles, decompound ; leaflets roundish-obovate or oblong, 

 3-lobed at the apex, lobes sharp, peduncles longer than the leaves. Flowers 

 perfect, white, in large panicles, very compound dia?cious or polygamous; 

 filaments somewhat club-shaped. Carpels strongly ribbed, sharp at both ends, 

 longer than the style. June and July. 



Geography. — Atlantic States, and west to Colorado. 



4. T. purpurascens, L. (Purplish Meadow Rue.) Stem 2 to 4 feet high, 

 purplish, smooth, or finely pubescent. Leaves roundish, or longer than wide, 

 wider towards the end, mostly 3-lobed, veins prominent, paler underneath, 

 margins rolled over. Flowers in compound panicles, purplish or with a 

 greenish tinge ; anthers nearly linear ; filaments broader at the ends ; anthers 

 drooping. May to July. 



Geography. — New York, Southern New England, south to Georgia, and 

 west to the Mississippi Valley. 



Var. ceriferum, C. F. Austin. Differs from T. purpurascens in having the 

 lower surface of the leaves and the fruit beset with waxy particles, and when 

 bruised exhales a peculiar, strong odor. 



Etymology. — Thalictrum is from the Greek word edWoo. spring forth green, 

 in allusion to the bright green foliage of the young shoots. The specific 

 names are: Dioicum, thus named because the flowers are sometimes dia'cions 

 or dioicous. Purpnrascen.'>, purplish thalictrum. Ceri/ennn, wax-bearing. 

 Cornuti, for a French physician, Conuitus. Clavatum, club-shaped, due to the 

 form of the filaments of this species. 



CALTHA, L. (Cow.slip. ^Larsh INLarigold.) Sepals 5 to 0, bright 

 yellow, petal-like. Petals wanting. Pistils 5 to 10, styles very sliort. 



