THE LEAVES. 



23 



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 



(fig- 137). 



154. 3. The leaf 

 blade. — To this part of 

 the leaf the word ' ' leaf ' ' 

 itself is frequently ap- 

 plied. In general, the 

 :he leaf blade is so broadly 

 winged as to be thin and 



clasping base. flat . but ^ gradations 



she. uli 



forming 



Potygvnu 



above the sheathing leaf base . 

 cut-off leaf f: cc, the stem; ca, an axillary 

 shoot. Natural size. — Alter Frank. 

 FlG. 141.— Leaf of Tklaspi 

 Natural size. — After Prantl 



Fig. 142. Fir.. 143. 



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

 size— After Cray. 



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

 About half natural size.— After ( Iray 



