iiS 



RANUNCULACEAE. 



Vol. II. 



24. THALICTRUM [Tourn.] L. Sp. PI. 545. 1753. 

 Erect perennial herbs. Leaves ternately decompound, basal and cauline, the latter alter- 

 nate. Flowers perfect, polygamous or dioecious, generally small, greenish-white or purplish, 

 panicled or racemed. Sepals 4 or 5, caducous or early deciduous. Petals none. Achenes 

 commonly few, one-seeded, ribbed or nerved, inflated in some species, stipitate or sessile. 

 Stamens 00, exserted. [Derivation doubtful, name used for same plant by Dioscorides.] 



A genus of about 85 species, most abundant in the north temperate zone, a few in the Andes of 

 South America, India and South Africa. In addition to the species described below, about 12 others 

 are North American, natives of the Southern States, the Rocky Mountains and the Pacific Coast. 

 Type species : Thalictrum foetidum L. 

 Flowers perfect. 



Stem simple, scape-likfe ; achenes sessile ; filaments slender. 

 Stem branched, leafy ; achenes long-stipitate ; filaments petal-like. 

 Flowers dioecious or polygamous. 

 Achenes distinctly stipitate. 



Roots bright yellow ; terminal leaflets not wider than long. 

 Roots not yellow ; terminal leaflets wider than long. 

 Achenes sessile or nearly so. 



Leaflets waxy-glandular beneath. 

 Leaflets not waxy-glandular. 



Filaments capillary or slightly thickened upward. 



Leaflets oblong, longer than wide, mostly puberulent beneath. 

 Leaflets suborbicular, pale and glabrous beneath. 

 Achenes thick-walled, indistinctly ridged. 

 Achenes thin-walled, distinctly ribbed. 

 Filaments club-shaped, often as wide as the anthers. 



T. aJpinum. 

 T. clavaHtni. 



T. coriaceum. 



T. caulophylloides. 



5. T, revolutum. 



6. T. dasycarpum, 



7. T. z'enulositm. 



8. T. dioicum. 



9. T, polygamum. 



I. Thalictrum alpinum L. Arctic or Dwarf 

 Meadow-Rue. Fig. 1932. 



Thalictrum alpinum L. Sp. PI. 545. 1753. 



Smooth or slightly glandular, i'-i2' high. Leaves 

 small, tufted at the summits of scaly rootstocks, biter- 

 nate ; the scapiform stem -leafless or i-leaved near the 

 base; leaflets cuneate-obovate or orbicular, firm, 3-5- 

 lobed at the apex, margins revolute ; panicle very simple, 

 often racemose; flowers perfect; stamens about 10; 

 filaments filiform, about equalling the sepals ; anthers 

 oblong-linear, mucrbnate; stigma linear; achenes i\" 

 long, obliquely obovoid, sessile, 



Anticosti, Newfoundland and arctic America generally. 

 Also in the Rocky Mountains, and in Europe and Asia. 

 Summer. 



2. Thalictrum clavatum DC. Moun- 

 tain Meadow-Rue, Fig. 1933. 



Tlialiclrum clai'atiim DC. Syst, i: 171. 1818. 



Glabrous, branching, 6'-24' high. Leaves 

 basal and cauline, biternate; leaflets oval, 

 ovate, or the terminal obovate-cuneate, thin, 

 pale beneath, stalked, with 3 main lobes and a 

 few secondary ones, their margins not revo- 

 lute; inflorescence cymose ; flowers perfect; 

 filaments clavate and petal-like ; anthers ob- 

 long, blunt; achenes spreading, equalling 

 their stipes or longer, obliquely oblong, nar- 

 rowed at each end, flattened ; stigma minute. 



Mountains of Virginia and West Virginia to 

 Georgia and Alabama. Slender meadow-rue. 

 May-Iune. 



