FIELDBOOK OF ILLINOIS WILD FLOWERS 
which rise many fleshy and food-storing scales or modified 
leaves that overlap and form a hard-packed, ovoid mass. The 
lily and the onion grow from bulbs. | 
That form of underground stem which is short and solid, 
usually flattened from top to bottom, and stored with plant 
food, is called a corm, of which the Jack in the pulpit is a good 
example. 
A stolon, frequently called a runner, is a horizontal stem 
which extends over the ground until the tip takes root and 
aS 
a b C 
Fig. 1—CompLerte, SIMPLE AND COMPOUND LEAVES. a.—Simple 
leaf, complete with stipules. b.—Pinnately compound leaf. ¢.— 
Palmately compound leaf. 
at the same place produces leaves and flowers, propagating a 
new plant. Runners of the strawberry are known to everyone. 
A tendril is a coiled slender outgrowth of a leaf or stem 
which usually assists in supporting the plant, and is commonly 
observed on vines. 
A scape is a naked flower stalk that rises from the ground 
and has the true stem structure. A tulip is probably the most 
familiar example. 
Leaves.—Leaves vary considerably in different kinds of 
plants, and so are used much more than roots and stems for 
purposes of identification. 
A complete leaf is composed of three parts: blade, petiole 
and stipules, fig. 1 a. The essential part of the leaf is the d/ade, 
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