CLASS XIX. ORDER I. 31] 



underneath, pinnatifid, half the lobes divaricated, tipt with long 

 and very acute spines. Flowers terminal, purple, numerous, 

 above the middle size. Calyx ovate, contracted to a small neck, 

 its scales tipt with sharp, ascending spines, and connected with 

 a downy web. Receptacle hairy. Seed down feathery. — Flow- 

 ers from June to September. — Biennial. 



Cnicus discolor. Willcl. Tall Thistle. 



Leaves sessile, pinnatifid, hairy, downy under- 

 neath ; the segments two lobed, divaricate, spinous ; 

 calyx globular, pubescent, with ovate, appressed 

 scales, the spines spreading. 



A very slender, erect thistle, five or six feet high. Leaves 

 whitish-downy underneath ; flowers small, purple. — About thick- 

 ets. — August. — Biennial. 



Cnicus pumilus. Nutt. Pasture Thistle. 



Stem hairy ; leaves green on both sides, clasping, 

 oblong-lanceolate and pinnatifid, the segments irregu- 

 larly lobed, ciliated and spinous ; calyx round-ovate, 

 naked ; scales spinous. 



Very common in dry pastures and by road sides. Stem thick, 

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

 August. — Biennial. 



332. ONOPORDON. 

 Onopordon Acanthium. L. Cotton Thistle. 



Calyx scales spreading every way, awl shaped ; 

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



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- 



