8 



Bulletin 194 



Leaves are either persistent, as in most of our conifers, which 

 remain green all winter, or they assume various colors with the coming 

 of the frost, and drop to the ground early in autumn although often they 

 hang dead and lifeless far into the winter. The characteristics of 

 leaves which we are accustomed to consider in determining their rela- 



III. LEAF MARGINS 



IV. PARTS OF A FLOWER 



Serrate. Doubly Serrate. Dentate. Crenate. Undulate. Sinuate. Lobed. 



tionships are their position or arrangement on the branch, whether 

 simple or compound, size, shape, texture, color, the amount and char- 

 acter of pubescence, the character of the margin, venation, etc. The 

 following diagrams will serve to illustrate some of the ordinary forms 

 and shapes of leaves, their margins, etc. 



Flowers. — Every tree when old enough bears flowers in its proper 

 season. Some of these, as the hawthorns, locusts and horse-chestnuts, 



are very showy ; others, like the 

 oaks and hickories, are compara- 

 tively inconspicuous. Some are 

 brilliantly colored, while others 

 are of the same color as the 

 leaves. Nevertheless, the flowers 

 are very accurate means of clas- 

 sification, and the only drawback 

 to their use for this purpose is 

 the fact that they last for such a 

 little while each year. 



Just as there are male and 



female in the animal world, so 



the male and the female are 



found in the plant world. A few of our trees, as the locu.st, basswood 



and clierry, have perfect flowers, bearing ])oth stamens and pistil. The 



Perfect Flower. 



a. Sepal (Calyx). 



b. Petal (Corolla). 



c. Stamen. 

 <1. Pistil. 

 e. Anther. 



Stamen. Pistil. 



f. Filament, 

 i,". Stigma, 

 h. Style. 

 i. Ovary. 



