100 



OUTLINES OP PLANT LIFE. 



flattened and leaf-like ones. The stipules may remain 

 attached to the base throughout the life of the leaf, or may 

 fall away early. Usually the two are separate, but they may 

 be united with the leaf base itself, forming wings for it, as 

 in roses (fig. 90), or they may be united with one another so 

 as to form a sort of sheath encircling the stem (fig. 91). 

 When the leaf base is winged, the wings extend downward 



Fig. 89. — A growing shoot of a thorn {Cratagus punctata), «, leaves developed as 

 bud scales which protected the parts above when in -the bud ; 6", stipules. Natural 

 size. — After Reinke. 



as lobes more or less encircling the stem. In many cases 

 the leaf is said to be clasping (fig. 92). These lobes may 

 even unite on the other side of the stem, so that the stem 

 seems to penetrate the base of the blade (fig. 93). When 

 two leaves occur at the same node, corresponding lobes 

 of the leaf bases may unite, so that the stem seems to pass 

 through the center of a leaf which extends equally on each 

 side of it (fig. 94). 



