SPECIES AND VARIETIES. 265 



by a single globular cluster of flower-head s, or throwing out 

 immediately under it 2-3 branches, each ending in a similar 

 cluster ; leaves erect, lanceolate or linear, pointed or obtuse, 

 sometimes slightly spathulate ; flower-heads very small, 20-30 

 in each cluster, the involucres ovoid-conical, more or less an- 

 gular, pale yellow or brown, the bracts usually acute. Dry 

 pastures, and stony or sandy wastes. Fl. July, August. 



F. apiculata and F. spathulata are sometimes distinguished 

 from the above, by their shorter or longer, and more or 

 less obtuse or acute floral leaves, by the quantity of cotton on 

 their involucres, and by their obtuse or acute bracts. 



P. minima : annual ; more slender and smaller than the 

 last, which it resembles ; stems more irregularly branched at 

 top, leaves smaller, clusters of flower-heads smaller and more 

 numerous, consisting of 3-10 minute conical heads. Fields, 

 and stony or sandy wastes. Fl. June to September. 



(158) Arctium. BURDOCK. 



A. Lappa : biennial ; stems stout, erect, branching, 3-5 feet 

 high ; leaves heart-shaped, large, sometimes \\ feet in length, 

 the upper ones broadly ovate, green above, white and cottony 

 beneath ; flower-heads in terminal panicles ; involucres nearly 

 globular, the bracts numerous with spiny hooked points, gla- 

 brous or covered with loose, white, cottony wool ; florets pur- 

 ple, equal. Waste places, roadsides, etc. Fl. July, August. 

 This paries much in the size of the flower-heads and in some 

 other points, and is sometimes divided into five species. 



(159) Carlina. CARLINE THISTLE. 



C. vulgaris : biennial ; stem erect, corymbose, 6-8 inches 

 high; leaves oblong-lanceolate, toothed or pinnatifid, very 



