324 COMPOSITiE. Liatris. 



Subtribe 1. Eupatorie.e, DC. Heads discoid ; the Jlowers all perfect and similar, usually 

 white, rose-color or purple (rarely cream-color), never yelloio. 



2. LIATRIS. Schreb. gen. p. 54:2 ; Endl. gen. 2210. BUTTON SNAKEROOT. 



[A name of unknown derivation.] 



Heads few, many-flowered. Scales of the involucre few or numerous, imbricate, not striate. 

 Receptacle naked. Corolla tubular, 5-lobed ; the lobes usually elongated. Branches of 

 the style much exserted, cylindraceous or somewhat flattened, obtuse. Achenia nearly 

 terete, tapering to the base, about 10-ribbed. Pappus of numerous plumose or barbellate 

 bristles, — Perennial herbs, with simple stems and a tuberous root. Leaves alternate or 

 scattered, usually lanceolate or linear and entire, with a rigid or cartilaginous margin. 

 Heads disposed in an elongated spike or raceme (flowering from the summit downward), 

 sometimes paniculate, rarely corymbose. Flowers purple (very rarely pale or white) ; the 

 corolla, style, etc. commonly dotted with resinous globules. — Very showy plants when in 

 flower. 



§. EuLiATRis, Torr. & Gr. Root a globose tuber : leaves linear or lanceolate, grass-like, 1-5- 

 nerved, mostly punctate with impressed and resinous dots : heads in a virgate spike or raceme : 

 involucre manif'stly imbricate : lobes of the corolla lanceolate or linear : pappus phi,r:>.ose or 

 plumose-barbellate. 



1. Liatris cylindracea, Michx. Small Button- Snakcroot. 



Smooth or slightly hairy ; stem (low) leafy ; leaves linear and lanceolate-linear, rigid, 

 scarcely punctate, mostly one-nerved ; heads few (1-7, rarely more), turbinate-cylindrical, 

 sessile or pedicellate, 16 - 20-flowered ; scales of the involucre numerous, all short and ap- 

 pressed, with rounded or obtuse abruptly mucronate tips, often ciliate, not punctate ; achenia 

 pubescent ; pappus very plumose. — Michx. fl. 2. p. 93 ; Ell. sk. 2. p. 275 ; DC. prodr. 5. 

 p. 130, not of Pursh ; Torr. 4- Gr. fl. N. A?n. 2. p. 69. L. stricta, M'Nab in Edinb. phil. 

 joiirn. 19. p. 60. L. flexuosa, Thomas in Sill, journ. 37. p. 328, with a figure. 



Stem 6-18 inches high, straight or somewhat flexuous. Leaves 6-10 inches long, the 

 lower ones broader and somewhat lanceolate. Heads about an inch long ; the pedicels often 

 an inch or more in length, but frequently almost none. Exterior scales commonly short and 

 broad, rarely a little prolonged and foliaceous. Flowers bright purple. Lobes of the corolla 

 hairy inside. 



Banks of the Niagara river, near the Falls, on tlie cast side {Mr. D. Thomas). Fl. August. 

 The specimens from this locality have the stem more flexuous, and the heads with longer 

 pedicels than usual. 



