HOW PLANTS AEE SCATTEEED 



383 



Why do bur-bearing plants often carry their fruit until 

 late winter or early spring? 



What reason can be given for the fact that the burdock, 

 the cocklebur, the beggar's-ticks, the hound's-tongue, and 

 many other common burs, are among the most persistent 

 of weeds ? 



453. Uses of Stone Fruits and of Fleshy Fruits to the 

 Plant. — Besides the dry fruits, of which some of the 

 principal kinds have been mentioned, there are many kinds 



Fie. 272. — Burs. 



A, Bticktights ; B, stioktights, two segments, magnified ; 

 C, turdock ; D, oookleburs. 



of Stone fruits and other fleshy fruits (Sects. 242-247). 

 Of these the great majority are eatable by man or some of 

 the lower animals, and oftentimes the amount of sugar 

 and other food material which they contain is very con- 

 siderable. It is a well-recognized principle of botany, and 



