How Plants Secure Change of Location 



389 



the ovary forms a very loose envelope, or in some Orchids, where 

 it is made from a greatly inflated seed coat (figure 158). In 

 all of these cases the principle is the same, — that of a great spread 

 of surface accompanied by very light weight. 



Another fine method for giving much surface, consists in the 

 provision of long soft hairs, or plumes; and seeds displaying this 

 arrangement are plenty. The Cotton seed, for example (fig- 

 ure 159), develops hairs of such number and length that they 

 serve not only to spread it afar under action of wind, but prove 



Fig. 158.— The 

 seed of an Or- 

 chid, showing 

 through i t s 

 loose b 1 a d- 

 der-like coat. 



Fig. 159. — A cotton seed, with 

 its long soft hairs. 



Fig. 160. — A 

 plumose fruit 

 of Clematis. 



Fig. 161.— The 

 par achut e 

 fruit of the 

 Dandelion 



incidentally a great utility to man, since they yield him the fiber 

 for the conmionest of all of his fabrics. The familiar silky plume 

 of the Clematis (or Virgin's Bower) is made by the outgrowth of 

 hairs from the style (figure 160); the parachute plume of the 

 Dandehon from the calyx; the soft tuft of the Milkweed from the 

 seed coat; the nebulous mass of the Smoke bush from stalks of 

 unfruitful flowers. The phrase "parachute plume" used above 

 was carefully chosen because of its suitability. For in the Dan- 

 delion (figure 161), and some other plants, the plmiies are spread 

 out horizontally, and keep that position in flight because of the 



