COMPOSITE FAMILY. 199 



of radical leaves, and deprive the rhizoma of all connection or communi- 

 cation with the atmosphere. 



The following notice of this annoying weed, from CURTIS' Flora Lon- 

 dinensis, may not be uninteresting to the American farmer : 



" Vitium agrorum apud nos primarium est [it is the greatest pest of 

 our fields.] LINNAEUS observes in his Flora Lapponica. The same may be 

 said with us : and we have bestowed on this plant the harsh name of 

 cursed, with a view to awaken the attention of the Agriculturists of our 

 country to its nature and pernicious effects. 



" Repeated observation has convinced us that many husbandmen are 

 ignorant of its economy, and while they remain so, they will not be 

 likely to get rid of one of the greatest pests which can affect their corn- 

 fields and pastures. Of the thistle tribe the greatest part are annual or 

 biennial, and hence easily destroyed. Some few are not only perennial, 

 but have powerfully creeping roots, and none so much as the present. 

 In pulling this plant out of the ground, we draw up a long slender root, 

 which many are apt to consider as the whole of it ; but if those employ- 

 ed in such business examine the roots so drawn up, they will find every 

 one of them broken off at the end : for the root passes perpendicularly to 

 a groat depth, and then branches out horizontally under ground." 



Two or three other species of Cirsium are frequently to be met with, 

 (viz. : C. nmti'cuin, MX., with the heads not spinose, and C. altis'si- 

 lHUTn, Spreng., with the stem-leaves not pinnatifid) : but, as they do not 

 incline much to infest the open grounds or farm-land, I have not judged 

 it necessary to notice them more particularly here. 



20. ONOPOR'DON, Vaill COTTON THISTLE. 



Heads and flowers nearly as in Cirsium. Scales of the involucre coria- 

 ceous, tipped with a lanceolate prickly appendage. Receptacle deeply 

 honey-combed. Ackcnia 4-angled, wrinkled. Pappus of numerous bris- 

 tles, slender, not plumose, united at the base into a horny ring. Coarse 

 herbs ; the stem winged with the decurrent base of the prickly-lobed 

 leaves. 



1. 0. Acan'thium, L. Stem and leaves cotton-woolly ; scales of the invo- 

 lucre linear awl-shaped. 

 Cotton Thistle. 



Annual. Stem 2-4 feet high, broadly winged by the decurrent edges of the leaves. 

 Leaves ovate-oblong, sinuate and spinose, woolly on both sides but most so beneath. 

 Flowers large purple, solitary at the end of the branches. Involucre globose, of nume- 

 rous lanceolate very pungent scales, green with yellowish tips, the upper ones nearly erect, 

 the middle ones spreading, the lowermost reflexed, all connected by a cottony wob. 

 Pappus scarcely half the length of the florets, jointed, rough downwards. 



Naturaliz3d from Europe. July -August. 



Obs. A coarse thistle-like plant, conspicuous by the white cottony 

 appearance of its stem and leaves. Very common along road-sides and 

 in waste places in New England. This is said to be the true Scotch this- 

 tle, the national emblem. 



