34 OBJECT LESSONS IN BOTANY. 
45. A winged petiole is flattened horizontally. A sheath- 
ing petiole embraces the stem with its winged edges like a 
sheath. You can find plenty of examples of these forms. 
Fig. 88. Rose,—stipules adnate. Fig. 84. Violet (V. tricolor),—gashed stipules. 
46. Let us now study more particularly the varying forms 
of the stipules. We have already defined them. (See Les- 
son J.,§ 4.) Here is seen the leaf of a Rose and of a Pansy 
(Figs. 83, 84), both with quite showy stipules. The former 
i] ; 
bes 
ak 85 i" 88 
Fig. 85. Leaf of Conioselinnm,—tri-pinnate, with sheathing petiole. 
Fig. 85. Leaf of Polygonum Pennsylvanicum, with its (s) ochrea. 
Fig. 87. Stem of Grass, with joint (J), leaf (2), ligule (8). 
Fg. 88, Leaf of Pear-tree, with slender stipules. 
45. What difference between a winged and compressed petiole? Can you 
describe a sheathing petiole? Give examples of these three forms. 
