DISTRIBUTION OF SPORES AMD SEEDS. iyj 



by folds, hairs, and other outgrowths upon the flower-leaves 

 or on the essential organs (fig. 238). (ii) Obstructions out- 



FiG. 238. — Flower of Cobcen scandens, halved; showing tufts of hairs on the base of 

 the filaments, of which there are five ; these close the bottom of the corolla cup, where 

 nectar is secreted, against intruders. Three-fifths natural size. — After Kemer. 



side the flower may exclude crawling insects. Such are sticky 



surfaces and hairs (fig. 239), moats about the stem formed by 



cup-shaped leaves holding 



water, or those formed by 



water in which swamp plants ' 



grow. (iii) The time of 



blooming also prevents the 



visits of any insects except 



those flying at that particular 



season. 



III. Adaptations to the 

 distribution of seeds. 



395. After the 

 of the seed various 



ripening 



Fig. 239.— Flower of a saxifrage (.S'«jr(/Va^« 

 devices controversa\ protected against invasion 

 by the numerous sticky glandular hairs on 

 and forces operate to scatter the flower stalk, ovulary, and calyx. Mag- 

 • f nified several diam. — After Kerner. 



them at as great a distance as 



possible from the parent, so that the young plants will not 

 come into competition with the old ones or with each other. 

 This object, which is secured in lower plants by the distri- 

 bution of the spores, can only be attained in seed-plants by 



