118 The Ohio Journal of Scie?tce [Vol. XVII, No. 4, 



Isopyrum L. 



Erect glabrous herbs, with slender stems and ternately 

 decompound leaves. Roots fibrous. Flowers white, solitary, 

 terminal; sepals 5-6 petaloid, deciduous; stamens numerous; 

 carpels 2-20. Follicles forming a head. 



1. Isopyrum biternatum (Raf.) T. & G. False Rue- 

 anemone. Stems branching. Basal leaves with long slender 

 petioles, thin, ultimate leaflets 3-lobed, broadly ovate. Sepals 

 5, white, }>4 in. long; petals none; carpels about four. Follicles 

 spreading, tipped with a beak. Moist woods and thickets. 

 South-west fourth of state; also in Cuyahoga County. 



Thalictrum (Tourn.) L. Meadow-rue. 



Tall erect perennial herbs with ternately decompound 

 leaves. Stem leaves alternate. Flowers small, greenish- white, 

 in loose panicles; sepals deciduous; petals none; stamens 

 numerous; carpels several; may be diecious. Achenes usually 

 beaked. 



1. Filaments slender, fibrous. 2. 



1. Filaments stout, nearly as broad as the anthers; leaflets sub-orbicular; 



plant stout and tall. T. polyganmm. 



2. Leaflets .sub-orbicular; plant slender, 1-3 ft. tall. T. dioicum. 

 2. Leaflets oblong; plant stout, tall. T. dasycarpum. 



1. Thalictrum dioicum L. Early Meadow-rue. Stems 

 slender, glabrous. Leaves slender, petioled, ultimate leaflets 

 orbicular, thin, pale beneath, 5-9 lobed. Flowers diecious 

 green, in spreading panicle of lateral umbels or corymbs; 

 anthers long. Achenes ribbed. Open woods and fence corners. 

 General. 



2. Thalictrum dasycarpum Fisch. & Lall. Purplish Meadow- 

 rue. Stems stout, purpUsh, 4-7 ft. tall, leafy branching. 

 Leaves sessile, leaflets oblong or obvate, 3 apical lobes, glabrous, 

 dark green above, lighter and pubescent below. Panicles 

 loose, compound. Achenes with 6 or S wings. Open woods 

 and meadows. General. 



3. Thalictrum polygamum Muhl. Tall Meadow-rue. Stems 

 stout, branching and leafy, 3-11 ft. tall. Stem leaves sessile; 

 leaflets obovate or lanceolate, some with 3 apical lobes. Pan- 

 icles compound, leafy. Anthers short. Rather general. 



