6 



FIELD AND WOODLAND PLANTS 



Attention to the form and character of the leaf is often of as 

 much importance as the observation of the flower in the deter- 

 mination of species. Not only should we note the general shape of 

 the leaf, but also the character of its surface, its margin, and its 

 apex. The surface may be smooth, hairy, downy, velvety, shaggy, 

 rough, wrinkled or dotted. The margin is said to be entire when it 

 is not broken by incisions of any kind. If not entire it may be 

 toothed, serrate (sawlike), crenate or wavy. Sometimes it happens 

 that the teeth bear still smaller teeth, in which case the margin 

 is said to be doubly toothed ; or, if the teeth are sawUke, it is doubly 

 serrate. As regards the apex, it is generally sufficient to note 



whether it is acute 

 (sharp), obtuse 

 (blunt), or bifid 

 (divided into two). 

 It is not neces- 

 sary to describe 

 separately all the 

 principal forms of 

 simple and com- 

 pound leaves. 

 These are illus- 

 trated, and the 

 student should either make himself acquainted with the terms 

 applied to the different shapes, or refer, as occasion requires, to the 

 illustrations. Concerning the compound leaves, however, theii* 

 segments are themselves sometimes divided after the manner of 

 the whole, and even the secondary segments may be similarly 

 cut. Thus, if the segments of a pinnate leaf are themselves pinnately 

 compound, the leaf is said to be bi-pinnate ; and, if the secondary 

 segments are also compound, it is a tri-pinnate leaf. 



1. Entire. 



2. Serrate or sawlike 



3. Doubly serrate. 



3 4 5 G 7 



MARfJINS OP LEAVES 



4. Dentate 6. Doublj^ crenate. 



or toothed. 

 Crenate. 



binuate or wavy. 



Inflorescence 



We must now turn our attention to the different kinds of 

 inflorescence or arrangement of flowers. Flowers are commonly 

 mounted on stalks (peduncles), but in many cases they have no 

 stalks, being attached directly to the stem of the plant, and tlierefore 

 said to be sessile. Whether stalked or sessile, if they arise from 

 the axils of the leaves — the angles formed by the leaf-stalks and 

 the stem — they are said to be axillary. When only one flower 



