FRUITS AND SEEDS 



137 



7. Many of these small hard seeds are destroyed in 

 the stomachs of the birds, but some pass through the 

 birds unhurt. Also, you must remember that many 

 birds expel seeds from their mouths in pellets. These 

 seeds are not hurt, and, indeed, such seeds germinate 

 more easily than ordinary seeds. Crows often eject 

 pellets of seed, and probably do more to spread plants 

 than any other birds. 



8. Sticky seeds. Some of the small dry seeds, 

 such as the seeds of rib-grass and groundsel (fig. 99), 



become sticky ; and this 

 helps them to catch on to 

 birds and animals. Among 

 shrubs, too, we have some 

 plants like Victorian laurel 

 that have smooth seed-cases 

 enclosing sticky seeds. 

 Others, like the plumbago, 

 have a sticky calyx that 

 closes over the ripe seed. 

 You know the plumbago 

 with its pale blue flowers 

 that give beauty to many an ugly fence ? After the 

 long, blue tube-corolla has done its work, it twists 

 up so as to form a kind of hook. Meantime, the calyx 

 that encloses the fruit frees itself from the stem 

 and hangs out to catch on to animals by its sticky 

 hooks. Though quite detached from its stalk, the 

 fruit holds on to the plant by these hooks, or by the 

 withered, twisted corolla. Brush against the plant 

 when the seeds are ripe, and notice how the seed- 

 cases stick to your coat. 



Groundsel. 



