312 CLASS XIX. ORDER I. 



cle cellular, like a honeycomb. Down rough, short. The Cot- 

 ton thistle was probably introduced from Europe. — It flowers in 

 July and August. 



333. LIATRIS. 

 LiATRis scARiosA. IViUd. Commo7i Liatris. 



Stem simple, somewhat pubescent ; leaves lanceo- 

 late, attenuated at both ends, smooth with a roitgh 

 margin; flowers racemed, alternate, distant; calyx 

 loose with spatulate scales, having a membranous, 

 colored margin. 

 Syn. Liatris squarrulosa. Mr. 



SeRRATULA SCARIOSA. L. 



A very beautiful plant, with a long, erect raceme of bright 

 blue flowers. — In Danvers and other parts of Essex county. — 

 August. — Perenn ial. 



334. VERNONIA. 

 Vernonia Noveboracensis. IVillcl. Vernonia. 



Leaves lanceolate, rough, serrulate ; corymb fasti- 

 giate ; scales of the calyx filiform at top. Willd. 



Sjjn. Vernonia pr.i:alta. Hooker. 



Serratula Noveboracensis. L. 

 A tall plant, bearing a multitude of dark purple flowers, 

 which turn nearly black in decay. Stem about four feet high, 

 furrowed, purplish, branching at top. Leaves peduncled, lan- 

 ceolate, finely serrate, acuminate, paler underneath. Flowers 

 terminating the stem and branches, in a compound, flat topped 

 corymb. Scales of the calyx ending in a fine, slender awn. — 

 Found in moist situations. — September. — Perennial. 



335. BIDENS. 

 BiDENS FRONDOSA. L. Comniou Buvr Marygold, 



Flowers discoid ; outer calyx six times as long as 

 the flower, its leaves ciliate at base; lower leaves pin- 

 nate, upper ones ternate, lanceolate, serrate. Willd. 



