THE LEAVES. 



123 



When this flattening is extensive, so that the petiole becomes 

 thin and leaf-like and the blade is wanting, it functions as a 

 foliage leaf (fig. 144). Not infrequent- 

 ly, the petiole is winged, as in the orange. 

 It may be entirely wanting, in which 

 case the blade arises directly from the 

 base, as in most grasses 



(%• 137). 



154. 3. The leaf 



blade. — To this part of 



the leaf the word ' ' leaf ' ' 



itself is frequently ap- 



Fig. i 4 i. plied. In general, the 



Polygonum 



Fig 



Fig. 140. 

 r4o. — Stipules 



sheath, ., above the sheathing leaf baseToMhe^f blade is SO broadly 



cut-off leaf /: cc, the stem; ca, an axillary w ; ncrpr | o C f rt K A thin anrl 



shoot. Natural size.-After Frank. Winged as tO De tUHl and 



Fig. 141. — Leaf of Thlasfii with clasping base. 



Natural size. — After Prantl. 



flat ; but all gradations 



Fig. 142. Fig. 143. 



Fig. 142. — Shoot of Uvularia, showing perfoliate leaves below. About half natural 



size. — After Gray. 

 Fig. 143. — A shoot of wild honeysuckle, showing upper leaves connate-perfoliate. 



About half natural size. — After Gray. 



