SEED DISTRIBUTION 



171 



Fruits, clusters of fruits, and plants full of fruits are rolled 

 along the ground (especially over the snow) by the wind, 

 often for great distances, scattering seeds as they go. If it is a 

 whole plant that travels, or a large part of a plant, it is known 

 as a tumbleweed. Such are the Russian thistle (Salsola), 

 tumble-mustard (Sisymbrium), winged pigweed {Cycloloma), 

 ghost-plant (Amarantkui), and the fruit cluster of old-witch 

 grass (Panicum)', the white-pine 

 cone is an example of a single fruit 

 traveling in the same way. 



Many aquatic plants, as grasses, 

 rushes, sedges, water dock, lotus, 

 bur reed, and a multitude of other 

 species, have fruits or seeds which 

 float, often for long distances, and 

 then lodge and grow. 



Burs of many kinds (fig. 150) 

 lodge in the hair, fur, or feathers of 

 passing animals and are finally dis- 

 lodged in various distant places 

 where they may grow. 



163. Dispersal of edible seeds. 

 Edible seeds and fruits (such as 

 nuts, the grains, and berries) and 



stone fruits (like plums and cherries) are frequently swal- 

 lowed by animals and later voided undigested and in a con- 

 dition to grow. In this way wild cherries (fig. 151) and wild 

 apples are planted about pastures and in open woods. Also, 

 raspberry, currant, and gooseberry bushes, asparagus, and 

 bittersweet may be found growing in the forks of trees 

 (fig. 152). Squirrels, blue jays, and some other animals carry 

 away nuts and bury them, often leaving them to grow the 

 following spring. 1 



1 On the general subject of seed dispersal see Kerner-Oliver, Natural 

 History of Plants, pp. 833-877, Henry Holt and Company, New York; 

 also Beal, Seed Dispersal, Giun and Company, Boston. 



FIG. 152. Red rasp- 

 berry bush in fork 

 of a maple 



