170 COMPOSITE. 



homogamous ; when the marginal ones are pistillate or neuter and the 

 others are perfect or staminate, the head is termed heterogamous. The 

 flowers with a strap-shaped (Ugulate) corolla are termed rays, or ray-flow- 

 ers ; and when these are present the head is termed radiate. A head 

 composed entirely of tubular flowers is termed discoid, and tubular 

 flowers occupying the centre of a radiate flower make what is called the 

 dish. In some cases the staminate and pistillate flowers are upon different 

 individuals — then the plant is dioecious. The receptacle is paleaceous or 

 chaffy when covered with membranaceous scales, and naked when destitute 

 of them. 



To indicate, even in the most general way, the medicinal character of 

 such an immense order of plants is well-nigh impossible. It will suffice to 

 say that very many of them possess tonic properties, few are aromatic, 

 most are disagreeable, and none are poisonous. 



LIATKIS. — Button Snakeroot. 



Character of the Genus. — Heads few T - or many-flowered ; flowers all 

 tubular, perfect. Scales of the involucre few or many, imbricate, ap- 

 pressed. Keceptacle naked. Corolla 5-lobed, the lobes usually elongated. 

 Branches of the style much exserted, roundish or somewhat flattened, ob- 

 tuse. Achenia round, slender, tapering to the base, 10-ribbed. Pappus 

 of 10 to 40 plumose or barbellate bristles. 



Perennial herbs, with simple stems and tuberous roots. Leaves alter- 

 nate, usually lanceolate or linear, entire, with a rigid margin, often resin- 

 ous-dotted. Heads in an elongated spike or raceme, sometimes panicu- 

 late, rarely cymose ; flowers showy, rose-purple, rarely pale or white. 



Liatris spicata Willdenow. — Button Snakeroot, Devil's Bit, Colic Boot. 



Description. — Heads 8- to 12-flowered, one-fourth to one-half inch long, 

 sessile, in an elongated spike ; involucre C3dindrical-campanulate, obtuse 

 at the base, the numerous scales appressed, obtuse, punctate, and with 

 narrow, scarious, purplish margins, the inner ones oblong, the outer ovate 

 or oval. Pappus densely barbellate ; achenia hairy. 



Stem erect, 3 to 5 feet high, smooth, leafy, proceeding from a roundish 

 corm or tuber. Leaves very numerous, hairy on the veins beneath, punc- 

 tate, those of the stem linear, diminishing in length from below upward, 

 the radical ones also linear, but very long. 



Habitat. — In moist ground from Southern New York to Wisconsin and 

 southward. 



Liatris odoratissima Willdenow. — Vanilla .Plant, Deers Tongue. 



Description. — Heads small, 4- to 10-flowered, in a panicle or corymb ; 

 scales of the involucre few, slightly imbricated, spatulate-oblong. Corolla- 

 lobes short, ovate. Pappus minutely barbellate, not plumose. 



Stem simple or branched above, 2 to 4 feet high, from a short rhizome, 

 not tuberous. Leaves thick, somewhat glaucous, the radical ones obovate- 



