706 



Some Common Thistles. 



[march, 



singly or two or three clustered together at the end of the 

 branches. Each head is about I in. to in. in diameter, with 

 palish crimson-purple flowers (Fig. 10). The plant produces 

 seeds freely, and these germinate very easily in two or three 

 days when they are placed in suitable soil, The spear thistle 

 as met with in the fields is usually a biennial. I have, however, 

 flowered seedlings in one season, but such plants did not ripen 

 seeds satisfactorily, and were destroyed by frost in the autumn. 



Fig. i. — Spear Thistle {Cnims lanceolatus, Hoffm.). 



Ordinarily the plant during the first season of growth produces 

 a compact rosette of ovate-lanceolate leaves lying close to the 

 ground. In the second year a central stem is sent up, which 

 branches and bears flower-heads in which seeds are produced. 

 After the latter are ripe the plant dies. The seeds, however, are 

 borne away from the parent plant by means of the feathery 

 down or pappus. The distance which the seed is carried is 

 comparatively short, more usually less than 30 or 40 yards 

 rather than beyond this distance, and it varies with the state 

 of the weather. On dry, hot days the seed separates or dries 

 off the pappus almost as soon as it escapes from the flower-head 



