120- WAYSIDE WEEDS. 



sideSj referring the leaves of eacli plant to the 

 description given in the Floras.* 



The rose, the vetch, the ash-tree, have truly 

 compound leaves, that is, are composed of a number 

 of leaflets arranged upon a central petiole, and 

 jointed more or less distinctly to it, forming what 

 is called a pinnate leaf, in distinction from the 

 radiating or palmate compound leaf of the clover 

 (Fig. 74), of the strawberry, etc., etc. The umbel- 

 bearers, among others, offer us a large variety of 

 compound leaves. 



You will call to mind that, in describing a 

 perfect leaf, the petiole, or footstalk, was given as 

 one of the parts ; but long before this we expect 

 you have discovered that there are many leaves 

 which have no petiole at all, but are directly attached 

 to the main stem. These are called sessile, or 

 sitting leaves. When the attachment is a simple 

 one, when the leaf is not only closely attached to 

 the stem, but is prolonged down it, as you wiU find 

 in the thistle, it gets the name of decurrent, or 

 running down leaf j or when it more completely 

 envelopes the stem, it becomes sheathing, as in the 

 grass (Fig. 56). In the common teazle, the pairs 

 of opposite leaves join, or grow completely round 

 the stem, and then are called connate; whilst a 

 perfohate leaf is one which the stem seems,, as it 



* A " Mora" ia a book giving the deseriptioa and classification 

 of the plants of any particular district or country. 



