The Trees of Vermont 



9 



great majority, however, have unisexual flowers, bearing either stamens 

 or pistils, but not both. When both male and female flowers are found 

 on the same tree, the flowers are said to be monoecious, and when male 

 flowers occur on one tree and the female on a different tree, the flowers 

 are said to be dioecious. The cottonwood of New England is dioecious 

 and each little seed is surrounded by a tuft of long, white hairs which 

 enables the wind to carry it considerable distances from the parent 

 tree, to the disgust of people living within its range. The planting of 

 the cottonwood is forbidden within the bounds of several cities on ac- 

 count of this objection. Since it is desirable in some places to plant 

 this rapidly growing tree, as in cities burning large amounts of soft 



TYPES OF inflorescences 



"^W 



Spike. Raceme. Panicle. Corymb. 



Umbel. 



Cyme. 



coal, it is a distinct advantage to know that the male trees may be 

 planted safely, since they bear no seed and shed no "cotton." 



Before trees can produce fruit their flowers must be fertilized, 

 i. e., pollen from the anther of a stamen must come in contact with the 

 stigma of a pistil. Some flowers are self-fertilized and others are 

 cross-fertilized. For a long time it was not understood how fertiliza- 

 tion was accomplished, but now we know that many insects, like the 

 nectar-loving bees and butterflies, and in other instances the wind, 

 transport the pollen from one flower to another, often miles being 

 traversed before the right kind of flower or a flower in the right stage 

 of development is found. And many are the modifications of flowers 

 to insure this transference of pollen. 



Fruit. — So numerous and so varied are the forms of tree fruits 

 that it would be only confusing to state their characters. Some 

 fruits, such as the achenes of the poplars and willows, are so small 

 and light that they are carried long distances by the wind ; others, like 

 the hickory nuts and walnuts, are too heavy to be wind-blown. Many 

 fruits are of considerable economic and commercial importance and are 

 gathered and marketed on a large scale. Among these are the 

 hickory nuts, walnuts, chestnuts, etc. Some, not esteemed by man, 



