
THE LEAF 89 
parent plant, small plantlets grow from the notches (Fig. 83). 
These plantlets send roots into the soil and grow into large plants. 
Storage. Leaves that are spe- 
cialized for storage can be divided 
into three general classes: leaves 
with special water-storage tissue, 
those with special food-storage 
tissue, and those forming pock- 
ets which collect materials from 
which the roots absorb such sub- 
stances as are ordinarily obtained 
from the soil. 
Water storage. Some plants 
which grow in very dry regions 
have leaves that are greatly 
thickened by water-storage tis- 
sue. Such tissue is very prominent in the leaves of the century 
plant (Agave spp.). Special water-storage tissue is not confined to 
leaves that are greatly thickened, but also occurs in some which 
have the appearance of ordinary foliage leaves (Figs. 45, 47). 
This is true of such plants as the India rubber tree (F%cus elastica). 
Food storage. Ileshy 
bulbs are composed 
largely of thickened 
leaf bases, as in the 
onion (Fig. 84), or of 
whole leaves, as in 
lilies. In both cases 
the leafy part of the 

Fig. 83. Leaf of life plant (Bryo- 
phyllum pinnatum) producing small 
plants. (x 4) 









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VW 
VY 
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ONY 




bulb coo for the Fia. 84. Surface and sectional views of onion 
storage of food. - bulb formed of enlarged leaf bases. (x 4) 
Pocket leaves. A 
considerable number of epiphytic tropical plants have the lower 
portion of their leaves, or special leaves, modified into pocket- 
like structures, in which leaves, dust, and other débris collect. The 
roots grow into this débris and absorb materials from it (Fig. 493). 

