THE FRUIT 163 



The various terms which defiHe the position or direction of Uie 

 ovule (erect, ascending, etc.) apply ecpially to the seed : so also the 

 terms anatropous, ortliotropous, campylotropous,^ etc., as 

 already defined, and such terms as 



IIiLUM, or scar left where the seed stalk or fimicidus 

 has fallen away, or where the seed was attached directly 

 to the placenta if there was no seed stalk. 



Raphe, the line or ridge which runs from the hiliim 

 to the chalaza in anatropous and amphitropous seeds. 



CiiALAZA, the place wliere the seed coats and the kernel 

 or uucellus are organically connected, — at the hiliini in orthotropous 

 and campylotropous seeds, at the extremity of tlie raphe or tip of 

 the seed in other kinds. 



MiCROPYLE, answei'ing to the forumen or orifice of the ovale. 



ECOLOGY OF THE FRUIT AND SEED AS REGARDS DIS- 

 SEMINATION 



337. The word dissemination here signifies the scatter- 

 ing of the seeds. In a vast uuuiber of cases not onl}' the 

 seeds, but tlie entire fruits, are dispersed, the pericarp fur- 

 nishing the same protection to the seed that it 2)rovided 

 during the period of ripening, and furtliermore aiding 

 directly by its construction in the transportation or even 

 in tlie planting of the seed. 



338. The need of seed dispersal is plain, both for the 

 parent pjlant — wiiicli shouhl not be crowded by its own 

 offspring — and for the interests of the seedlings tliera- 

 selves. That an advantage is to be won through wide dis- 

 tribution of seed is shown by the fact that the seed or 

 the fruit is, in most species, adapted to the special work 

 of dissemination. 



339. The agents of dissemination are wind, water, and 

 animals. But a considerable number of plants are quite 

 independent of exterjial aid, being provided with s[)ecial 

 mechanisms for throwing tlieir seeds to a distance. 



340. Structures to accomplish dissemination through the 

 agency of the winds are exemplified l)y the wings of the 

 Elm and Maple fruits (Figs. 265, 266), the plume of 



1 For these terms see the section on the ovule, § 280. 



