The Natural Distribution of Forest- Tree Seeds. 31 



14. Pistillate Flow- 

 ers of the Willow. 



moisiure and light, nature lias provided many kinds witli the means 

 lor being carried to a greater or less distance. 

 This natural dispersion of the seed may occur in 

 various ways : 



123. Dispersion by the Winds. Most of the pines 

 and firs have their seeds furnished with a thin 

 membranous wing at one end, that enables them 

 to be borne to a considerable distance by the winds. 

 The elms have a thin disc entirely around the 

 seed, and the maples have their seeds in pairs, each 

 side being furnished with a membranous wing. In 

 the ash the seeds have closely adherent leaves, 

 which enable it to be carried by the winds, and in 

 the hornbeam there is a leaf-like appendage, that 

 aids in its dispersion. In the maples, the pairs 

 of seeds, with symmetrical wings, takes a _ ro- 

 tary, spinning motion as they fall. The poplars 

 and willows have a downy tuft, which enables 

 them to be carried by the winds, sometimes many 

 miles from the tree where they grew. 



124. The Cottonwood, which belongs to the 

 poplar family, derives its name from this downy 

 appendage, which lies abundantly scattered over 

 the ground at the season when it ripens. The 

 basswood has a heavier seed, suspended on the 

 underside of a leaf-like wing, which causes it to 

 shoot off obliquely as it falls. In some instances, 

 the seeds falling in winter upon a crust of snow, or 

 upon the ice, may glide along before the wind a 

 great distance, and in this way the pods of the lo- 

 cust, and other heavier seeds, in their capsules, or 

 without them, may occasionally be scattered. 



15. Pine Seeds. 



16. Seed of the Elm. 



Of the Agency of Animals in the Planting of Tree 

 Seeds. 



125. We often find trees, especially such as bear 

 edible nuts, or stone fruits surrounded by a pulp, growing in situa- 

 tions where the seeds have been dropped by birds or animals. In fact, 

 the squirrels may be called the most industrious and successful 



