THE STUDY OF LEAVES 21 



each other; while a few have three or more regularly 

 arranged around the same joint. These illustrate the 

 three common arrangements which leaves take — alternate 

 (one at a joint}, opposite (two at a joint), and whorled 

 (over two at a joint). 



There is another apparent arrangement of leaves whicli 

 will more or less bother the beginner and must be mas- 

 tered. This is where the leaves are clustered either at the 

 tips of the stems, as in the azaleas (Plate 1, Fig. D), or 

 in alternate bunches along the usually thorny branches, 

 as in the barberries (Plate I, Fig. E). Besides these ar- 

 rangements, which occur on the new growth, the old wood 

 will have clusters of two or more leaves where the leaves 

 were in the preceding year ; of course this is the bursting 

 and developing of the axillary buds and should produce 

 branches of the year instead of close clusters of leaves. 

 Usually branches do appear, but in a few species all the 

 axillary buds start and so most of them form only short 

 stunted side shoots which appear merely like a cluster of 

 leaves. One must not mistake these for whorls of leaves. 

 Where leaves are whorled, they are regularly arranged 

 around the stem at the joint, and are not a cluster either 

 at the tip or on the side of the stem. 



Kinds of Leaves. — Having reached the stage where the 

 whole leaf is readily determined, the next step is to know 

 how to use words exactly in describing leaf differences. 

 Most leaves or bushes consist more or less of a leaf 

 stalk and a single blade, the spreading portion; these 

 are called simple leaves, and numerous examples can 

 be found in any shrubbery. The viburnum, the mock 

 orange, and the maple have opposite simple leaves (Plate 

 II, Fig. K ; Plate III, Fig. N ; Plate IV, Fig. W ), while 

 the rhododendrons, the smoke bush, and the silverberry 

 have alternate simple leaves (Fig. 445 ; Plate I, Fig. F ; 

 Plate II, Fig. I). 



If the leaf has more than one blade, it is called compound. 

 The elder, the pagoda tree, the rose, and the buckeye 



