STIPULES AND TENDRILS. 



61 



which are called stipules. (Fig. 93.) Stipules frequently fall 

 off upon the development of the leaf, when they are called cadu- 

 cous ; at other times they remain as long as the leaf, and are 

 called persistent. In the former case they are attached only by 

 their base to the stem ; in the latter, they are connected with 

 the petiole and fall only with it. In opposite leaved plants, 

 the stipules corresponding to the two leaves are generally 

 united, forming but two stipules instead of four. The Hop 

 affords an example of this kind. The stipules are in many 

 respects analogous to leaves, and even have buds in their axils, 

 as in the Peach, and in some instances are very much like 

 them in appearance, as in the Pea. In others, they bear no 

 resemblance to the leaves, but are simple membranous append- 

 ages, as in the Hickory, or fine bristles, as in the Cherry. 

 They assume a great variety of appearances, by various modifi- 

 cations of structure and attachment. In the Rose, they are 

 attached to the petiole, forming a leaf-like margin to that 

 organ. In the Polygonum and Rhubarb, they form a sheath 

 round the stem by the union of their edges, and are then called 

 ochre^e. In some plants, they become hardened and conical, 

 and form spines. In climbing plants, they often lengthen into 

 a slender thread-like appendage, and become the organ by 

 which the plant attaches itself to objects over which it climbs ; 

 thus forming for the plant the means of support. But, how- 

 ever various may be their appearances, and however unlike in 

 structure, yet if they originate from the base of a leaf, they are 

 stipules. 



Fig. 93. 



Fig. 94 



Stipules. 



101. "What are stipules? How are they in opposite leaved plants ? How 

 in different plants mentioned ? What is an ochrea ? How in climbing 

 plants ? 



