DISTRIBUTION OF SPORES AND SEEDS. 365 



Hairs of the most various origin are produced in sucli 

 numbers and position as to form either parachutes or tangled 

 woolly envelopes to the fruit or seeds (figs. 410, 411). 



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Fig. 410. 



Vic. . 



Fig. 409. — Heads of fruits of the dandelion : single fruits falling, exposing common 



torus and involucre. Natural size. — .After Kemcr. 

 Fig. 410. — Fruits of a willow, burst, and allowing the seeds, each with a tuft of silky 



hairs (coma), to escape. Natural si,:e. — After Kemer. 



493. 4. Distribution by animals. — 'I'o secure this there 

 are two general methods observable, [a) The seed or fruit 

 is either adapted for transport by adhering to the bodv of the 

 animal ; or (//) the seeds are surrounded by edible parts, and at 

 the same time so protected against the digesti\e juices that 

 they may pass uninjured through the alimentary canal. A few 

 plants are distributed by animals which collect and hide their 

 fruits or seeds (e.g., the squirrels ). The adhesion of fruits or 

 seeds to animals, especially to those which are provided with 



