594 



WEED FLORA OF IOWA 



In the asters, ironweed, goldenrods, lamb's quarter, etc., there 

 is only one leaf at each node, and they are spoken of as alternate. 

 In some cases several leaves appear at each node in a whorl. Such 

 examples of whorled or verticillate leaves are found in the bed- 

 straws and Joe Pye weed. 



BRANCHING. 



The outline of a blade is extremely various. When the general 

 outline is completely filled out and the margin represents an even 

 line, the leaf is said to be entire. Examples of such leaves are 

 found in water pepper (Polygonum liydropipcr) , mild water pepper 

 (P. hydropiperoides), Pennsylvania smartweed (P. pennsylvani- 

 cum), etc. 



Fig. 447. Leaf of the Privet plant showing entire margin. 



To designate the amount and character of the branching, the 

 following terms are used: 



Fig. 44SII 



Fig. 448 'II Fig. 4481 V 



Fig. 448. I. Triangular, lobed leaf of the Notch-weed. II. The reniform or 

 kidney-shaped leaf of Ground Ivy, illustrating wavy margin, 

 shaped leaf of Bindweed. IV. Spear-shaped leaf of Sorrel. 

 (After Thome.) 



III. Arrow- 



