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 {Polygowum hydropiper) , mild water pepper 

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

 cutn), etc. 



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



To designate the amount and character of the branching, the 

 following terms are used: 



\ 



Fig. 448IV 



Fig. 4481 



Fig. 448. I. Triangular, Ipbed leaf of the Notch- weed. II. The renlform or 

 kidney-shaped leaf of Ground Ivy, Illustrating wavy margin. III. Arrow- 

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

 (After Thome.) 



Fig. 448II Fig. 448III 



Triangular, Ipbed leaf of the Notch-weed. II. 



