s:eed distribution. 



49 



meats combined. In the apple (Fig, li64) 



it is a fleshy, thickened disk, together with 

 the adnate calyx lined by it. In the check- 

 erberry (Pig. 265) it is the calyx only 



which becomes fleshy. In the gooseberry it 

 is the calyx and the entire ovary, but with- 

 out any disk, while in many other berry-like 

 fruits it is the ovary alone. In the plum 

 and cherry not all of the ovarian wall is 

 edible, its eudocarp becoming a putamen. 

 In the lemon, the pa paw (Fig. 2(57) and the 

 pumpkin it is the inner portion which is 



edible, while the outer is not. In the 



watermelon the placentae comprise almost 

 the whole of the edible portion, while in 

 the tamarind it is the middle layer of the 

 ovary. 

 In all of the above mentioned cases it 



is some one or more of the parts of the 

 flower which eventually forms the edible 



pericarp, but there are numerous cases 

 in which other parts of the plant contrib- 

 ute to or form the whole of such portion. 

 In the Cashew (Fig. 268) the ovary (a) 

 enlarges but little, while the petiole (b) 



Kg. a 67. 



undergoes a great enlargement and be- 

 comes edible. In the cactus (Fig. 242) 

 the end of the branch is hollowed out and 

 the wall so formed becomes the edible 

 pericarp of a single flower. In the fig 



(Fig. 269) we have a similar hollowed 

 branch, but instead of being occupied by 

 a single flower, the wall is lined by an 

 immense number of them. 



Besides the more common methods of 

 seed <listribution referable to the peri- 

 carp, which are thus subject to classifi- 

 cation, we find numerous special devices 

 which cannot here be enumerated in de- 

 tail. Fruits which grow beside or in the 

 vicinity of streams or other bodies of 

 water are commonly adapted in some way 

 for using the latter as a vehicle for trans- 

 portation. They are frequently of a 

 rounded form and of considerable weight, 

 so that upon falling they will roll into 

 the water, where they are then enabled 

 to float by virtue of low specific gravity, 

 due often to the presence in them of large 

 cavities. The pericarp is in such cases 

 usually furnished with some means of 

 protection against the action of the water. 

 Apparently the thick and woody pericarp 

 of the Dipteryx is so constructed in order 

 to avail itself of this method of trans- 

 portation. The fruit of a species of 

 Avena is so constructed that by the 

 change of form and position of its long 

 awns in dry and wet weather respectively 

 it is enabled to travel. 



Finally we must note that some fruits 

 are protected by special devices against 

 transportation. Thus the mangrove pos- 

 sesses a seed which germinates while still 

 attached to its parent and which does not 

 sever its connection therewith until the 

 young plant has descended many feet and 

 fixed itself into the mud below. The pea- 

 nut, after anthesis, drives its ovary be- 

 neath the surface of the soil, where its 

 fruit is developed. Plants possessing this 

 habit are always highly gregarious and in 

 this way occupy the ground to the exclu- 

 sion of all other species, thus securing 

 their perpetuation even though they are 

 not specially disseminated. The high de- 

 gree of adaptation secured by the peanut 

 is further illustrated by its apparent 

 power to support itself by means of these 

 buried branches should the parent stem in 

 any way become severed; a very impor- 

 tant protection in view of the highly nu- 

 tritious character of the herbage which 

 renders it liable to destruction by grazing 



animals. 



Mo. Bot. Garden, 



1896. 



