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 Lo7i- 

 dinensis, may not be uninteresting to the American farmer : 



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

 our fields.] Linx^us 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 undor ground." 



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

 (viz. : C. muti'cum, ^Wa:., with the heads not spinose, — and C. altis'si- 

 mnm, 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. 



26. 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. Achenia 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 reflcxed, all connected by a cottony web. 

 Pappus scarceh' half the length of the florets, jointed, rough downwards. 



Naturalized 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. 



