THE LEA VES. 



\2- 



?a 



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 frecjuently ap- 

 plied. In general, the 



FiG. 140,-Stipules of Poh'^'onum forming a j |- \^\^^t is SO hrOadlv 

 sheath. .'. above the sheathing leaf base j-, ot the 



cut-off leaf J. .y, the stem ; ca an axiUan' ^yjiip-ed aS tO be thill and 

 shout. Natural size. — After trank. o 



flat; but all gradations 



Fig. 141.— Leaf of Thlaspi with clasping base 

 Natural size. — After Pranll. 



<i:^ 



Fig. 142. Fig. 143. 



PiQ 1^2. — Shoot of Uz'ularia, sho^^■^Ilg perfoliate leaves below. .About half natural 



size.— .After Giav. , , • , i ,- 



Fig. I43-— -A shoot of -nild honeysuckle, showing upper leaves connate-perfohate. 



About half natural size. — .After Gray. 



