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 (ligulate) corolla are termed rays, or ray-Jloiv- 

 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 

 disk. In some cases the staminate and jjistillate 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 tr 

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

 most are disagreeable, and none are poisonous. 



LIATRIS.— Button Snakeroot. 



Character of the Genus. — Heads few- 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 barbeUate 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-jiurple, rai-ely j^ale 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 sj^ike ; involucre cyHndrical-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 barbeUate ; achenia hairy. 



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

 corm or tuber. Leaves very numerous, hairy on the veins beneath, j^un.- 

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

 the radical ones also linear, but very long. 



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

 southward. 



Liatris odoratissima "Willdenow. — Vanilla Plant, Deer's Tongue. 



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

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

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



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

 not tuberous. Leaves thick, somewhat glaucous, the radical ones obovat 



