SEED-DISPERSAL 261 



(Fig. 257), beggar-ticks (Fig. 258), stick seeds, etc.; and 

 similar appendages are developed in connection with the 

 involucres of cockle-bur 

 (Fig. 259, A), burdock 

 (Fig. 259, B), etc. 



Fleshy fruits are at- 

 tractive as food to cer- 

 tain birds and mam- 

 mals. Many of the 

 seeds (such as those of A 



grapes) may be able tO FIG. 259. Heads of cockle-bur (A) and burdock 



resist the attacks of the ^ i^.-\^K^^ nd&ge9 f the 

 digestive fluids and es- 

 cape from the alimentary tract in a condition to germi- 

 nate. As if to attract the attention of fruit-eating ani- 

 mals, fleshy fruits usually become brightly colored when 

 ripe, so that they are plainly seen in contrast with the 

 foliage, 



