402 



TREES AND SHRUBS. 



simple entire doubly-toothed leaves arranged alternately in 

 two side-rows on the stem. The blade is roughly heart- 

 shaped in outline, but one half (that nearest the tip of 



the twig, or that farthest from 

 it ?) comes off the leaf -stalk lower 

 down than the other half and 

 bulges out, so that the blade is 

 lopsided. 



The advantage of this lopsided- 

 ness is easy to observe if you hold 

 a leaf -bearing twig up to the light 

 and notice how the larger half of 

 each blade tends to fill up what 

 would be a space (if the leaf were 

 symmetrical) between the leaf , the 

 stem, and the leaf above. This 

 peculiarity of the leaf-blade, 

 enabling the leaves on a twig to 

 catch more light without too 

 much overlapping of each other, 

 is a simple method of producing 

 a leaf -mosaic; it is more pro- 

 nounced in the Wych Elm (leaf 3 to 6 ins. long, up to 3 ins. 

 across broadest part, taper-pointed) than in Common Elm 

 (leaf about 2 ins. long, not so pointed). 



In Wych Elm the crown is broader and the main branches 

 more spreading than in Common 

 Elm; the latter has its bark more 

 deeply furrowed. There are two 

 kinds of buds ; the higher ones are 

 pointed and grow into leafy shoots 

 (either long shoots or dwarf shoots), 

 while the globular lower buds pro- 

 duce clusters of flowers. The buds 

 have much the same structure as in 

 Hazel ; the young leaves have stipules 

 which soon fall off ; the branches, 

 like the leaves, are in two side rows ; the true end bud dies 

 off each year, and the uppermost side bud replaces it. 



The flower-buds open first, in March or April, each pro- 

 ducing a dense tuft of small brownish-green flowers ; each 



Fig. 169. The Elm, with Clusters 

 of Fruits. 



PERJANTH 



Fig. 170. Elm. 

 A, Flower ; B, Pistil. 



