70 



ELEMENTS OF STKUCTUIIAL liOTANY. 



Fig. 103. 



Thev must 



fact, hiilhlets, autl new plauts may be grown from them 

 96. Our Hawtiiorn is rendered 



formidable by the presence of stout 



s/iiites (Fig. 103) along the stem and 



branches. These sj)ines invariably 



proceed from the axik of leaves, 



and are, in fact, branches, whose 



growth has been arrested. They 



are appendages of the wood, and 



will remain attached to the stem, 



even after the bark is stripped off. 

 not be confounded with the j>rickh's (Fig. 104) 

 of the Eose and Brier, which belong strictly to 

 the bark, and come off with it. 



97. Fcliage-Leaves. These organs arc 

 usually more or less flat, and of a green colour. 

 In some plants, however, they are extremely 

 thick and succulent ; and in the case of para- 

 sites, such as Indian-Pipe and Beech-drops, 

 Fig. 104. ^-^Q-y are usually either white or brown, or of 



some colour other than green. The scaly leaves of 



underground stems are also, of course, destitute of 



colour. 



98. As a general thing, leaves are extended horizon- 

 tally from the stem or branch, and turn one side towards 

 the sky and the other towards the ground. But some 

 leaves are vertical, a)id in tlie case of the common Iris 

 each leaf is doubled lengthwise at the base, and sits 

 astride the next one within. Such leaves are accordingly 

 called etjnitant. 



99. As to their arrangement on the stem, leaves 

 are (dtemate when only one arises from each node (Fig. 

 3). If two are formed at cnch norle, they are sure to be 



istry ol Education, Ontario 

 Historical Collection 



