| Oblong. | Oval. | Orbicular. | Oblanceolate. | Spatulate. | Obovate. |
II. LEAF TIPS
| Acuminate. | Acute. | Obtuse. | Emarginate. | Mucronate. |
LEAVES.—With the advent of spring the buds of our broad-leaf trees swell and burst and the leaves come forth and clothe the trees with mantles of green, hiding the branches which have been bare through the cold winter months. The evergreens, too, take on new color and begin a new period of growth. It is the leaves which the beginner finds most interesting and in which he finds a ready means of identification. It must be remembered, however, that leaves vary greatly in size and shape and general appearance. How large are the leaves on a flourishing sprout and how small on a stunted tree of the same species growing near by, but under adverse circumstances. How different are the leaves of the big white oak standing in the yard; they are hardly lobed on the lowermost branches, while higher up they are deeply cut. Yet, in spite of the many modifications that leaves undergo, the leaves of any one species have certain rather constant characters which are found in all forms, and the student will have little difficulty in selecting and recognizing typical leaves.
III. LEAF MARGINS
Serrate. Doubly Serrate. Crenate. Undulate. Sinuate. Lobed. Dentate.
Leaves are either persistent, as in most of our conifers, which stay green all winter, or they turn various colors with the frost and fall early in autumn; often they hang dead and lifeless far into the winter. The points about leaves which we are accustomed to consider are the position or arrangement of the leaves on the branch, whether simple or compound, size, shape, texture, color, amount and character of pubescence, 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.