CHAPTER X 
THE LEAF 
The leaf is a usually flattened, rarely semi-centric, or centric- 
lateral expanse developed by the stem or by branches and in 
whose axil one or more branches arise. 
Fic. 150.—Complete leaf of Slippery Elm (Ulmus fulva). 1, lamina; p, petiole; 
5, stipules; mr, midrib; 2, secondary vein; st, branch to which leaf is attached. The 
margin of this leaf is doubly serrate. 
Leaves seldom develop buds over their surface or along their 
margin and in connection therewith roots. The capacity for bud 
development by the leaf is restricted to three families, viz.: Cras- 
sulacee, Begoniacee and Gesneracea. 
Tue Comptete Lear.—The leaf when complete consists of 
three parts, Jamina, petiole, and stipules. The Lamtna or BLapE 
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