78 A TEXTBOOK OF GENERAL BOTANY 
a blade (F ig. 69). The special functions for which some leaves 
are particularly suited may be grouped under six headings: 
support (stem function), absorption (root function), attraction of 
insects (floral function), reproduction (seed function), storage, 


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Fig. 66. Banana plant. (x #; 
and protection. These functions may be subsidiary to the ordi- 
nary functions of leaves, or be more important, or even replace 
the usual functions. 
Support (stem function). The primary function of stems is to 
support the aérial parts of the plants. This function is performed 
by four special types of leaves: tendrils, which may be modified 
whole leaves or parts of leaves; leaves with hooks; leaves with 
floats; and leaves that have supporting leaf bases. 
Supporting leaf bases. The leaf bases of the banana and other 
similar plants are greatly elongated and grow so close together 
as to produce a structure which has an appearance very much 
