SEEDS AND FRUITS CARRIED BY WIND 



83 



the Thistle, Dandelion, Wild Lettuce, Fiieweed, Ironweed, White 

 Weed, Fleabane, and others, the tufts of downy hairs on the small 

 dry fruits in which the seeds are enclosed enable the fruits with the 

 seeds to be lifted and carried many miles by the wind. In the 

 Milkweeds, the seeds bear long hairs which make them easily 

 carried by the wind. In some plants, as in the Curled and Smooth 

 Dock, Ash, Elm, and Maple, the fruits are winged and easily 

 borne away by a passing breeze. The fruits of some of the 



Fig. 85. — Some fruits and seeds disseminated by the wind, a, fruits of the 

 Basswood (T ilia Americana) and the leaf-like bract which floats in the air and 

 thereby scatters the fruits, h, samara or winged fruit of a Maple, c, fruit of 

 a Wild Lettuce {Lactuca Floridana). d, winged fruit of an Elm. e, pods of a 

 Milkweed {Asclepias syriaca) allowing the seeds to escape to be scattered by 

 the wind, a, c, and e from Hayden. 



Grasses are enclosed in chaff bearing long hairs and are easily 

 blown about. The fruits and seeds of Ragweeds, Velvet-leaf, 

 Docks, Pigweeds, Chickweeds, and some plants of the Grass fam- 

 ily are blown long distances over the surface of snow, ice, or 

 frozen ground. {Fig. 85.) 



Some plants break off near the ground after ripening their seeds 

 and are rolled over and over by the wind, dropping their seeds as 

 they go. These are known as the "tumble-weeds" and include 

 the Russian Thistle, Tumbling Mustard, Tumbling Pigweed, 

 Buffalo Bur, Old Witch Grass, and a number of others. {Fig. S6.) 



