84 SEEDS AND FRUITS 
Seeds and Fruits Carried by Water. — Plants, such as the 
Great Ragweed, Smartweeds, Bindweeds, Willows, Poplars, and 
Walnuts, which grow along streams, have their seeds and fruits 
floated away during overflows. Sometimes, when the banks of 
Fic. 86. — Plants of the tumble weed (Amaranthus albus) tumbling over 
the ground and scattering seeds as they go. After Bergen. 
streams cave off, plants with ripened seeds fall into the current 
bodily and are carried for miles down the stream, finally lodging 
in fields where their seeds grow. The seeds of plants growing on 
the upland are washed to the lowlands during rains and seed the 
bottom fields. Some fruits, as in case of the Coconut, are so 
resistant to salt water that they can be carried long distances by 
ocean currents. 
Seeds and Fruits Carried by Animals. — Birds eat the fruits 
of some plants for the outer pulp, and the hard seeds pass undi- 
gested. In this way the seeds of the Nightshades, Poison Ivy, 
Pokeweed, Blackberry, Pepper Grass, and others are distributed. 
Even the seeds and fruits of Thistles, Dandelion, Ragweeds, and 
Knotgrass may be eaten in such large quantities that many pass 
undigested and start new plants wherever they fall. Birds often 
carry sprigs of plants to places where the seeds may be eaten 
without molestation and in this way distribute seeds. (Fig. 87.) 
Birds that wade in the edge of ponds, lakes, and streams 
often carry away on their feet and legs mud containing seeds. 
