FEUITS AND SEEDS 



227 



If some pollen grains chance to adhere to the feathery 

 stigma, they develop a long tubular process by the protrusion 



Fig. 31.— Yodnq pistil of the barley. 



tt, stamen ; /, ovary ; n, stigma with feathery branches ; I, the tissue through which the 

 pollen tube grows ; 0, ovule ; i, the integuments ; m, micropyle ; e, embryo sac. 



of the delicate inner coating (intine) through the thin portions 

 of the hard outer coat (extine). This pollen tube makes its 



