Class XIX. Order I. 293 



about a foot in height, with a few very large purple flowers. 

 August. Biennial. 



309. ONOPORDON. 

 ONOPORDON ACANTHIUM. L. Cotton Thistle, 



Calyx scales spreading every way, awl shaped ; 

 leaves ovate-oblong, sinuated, woolly on both sides. Sm. 



Frequent in waste grounds, and readily distinguished from 

 the other thistles by its white appearance and the large size of 

 its leaves. Stem erect, tall, winged by the decurrent base of 

 the leaves. Leaves oblong, broad, sinuated, toothed, and spi- 

 nous, covered on both sides with a loose, white, cottony sub- 

 stance. Flowers purple. Calyx globose, wider than it is long, 

 with lanceolate, spreading, cottony, spinous scales. Recepta- 

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

 Cotton thistle was probably introduced from Europe. It flow- 

 ers in July and August. 



310. LIATRIS. 



LIATRIS SCARIOSA. Willd. Common Liatris. 



Stem simple, somewhat pubescent ; leaves lanceo- 

 late, attenuated at both ends, smooth with a rough 

 margin ; flowers racemed, alternate, distant ; calyx 

 loose with spatulate scales, having a membranous, 

 coloured margin. 



Sijn. LIATRIS SQUARRULOSA. MX. 

 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 Perennial. 



311. VERNONIA. 



VERNONIA NOVEBORACENSIS. Willd. Vcrnonia* 



Leaves lanceolate, rough, serrulate ; corymb fas- 

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



