LESSON 9.j 



PHILLODIA, STIPULES, ETC. 



69 



dar, and Arbor-Vitoe (Fig. 135), are different examples. These 

 last are leaves s'erving for foliage, but having as 

 little spread of surface as possible. They make 

 up for this, however, by their immense numbers. 



177. Sometimes the petiole expands and flattens, 

 and takes the place of the blade ; as in numerous 

 New Holland Acacias, some of which are now 

 common in greenhouses. Such counterfeit blades 

 are called phyUodia, — meaning leaf-like bodies. 

 They may be known from true blades by their 

 standing edgewise, their margins being, directed 

 upwards and downwards ; while in true blades the 

 faces look upwards and downwards ; excepting in 

 equitant leaves, as al- _ 



ready explained, and 

 in those which are 

 turr.ed edgewise by 



a twist, such as those of the Callis- 



temon or Bottle-brush Flower of our 



greenhouses, and other Dry Myrtles 



of New Holland, &c. 



178. Stipulcsi, the pair of appendages 



which is found at the base of the peti- 

 ole in many leaves (133), should also 



be considered in respect to their very 



varied forms and appearances. More 



commonly they appear like little blades, 



oiyeach side of the leaf-stalk, as in the 



Quince (Fig. 83), and more strikiugly 



in the Hawthorn and in the Pea. Here 



they remain as long as the rest of the 



leaf, and serve for the same purpose 



as the blade. Very commonly they 



serve for bud-scales, and fall off when 



the leaves expand, as in the Fig-tree, 



and the Magnolia (where they are large and conspicuous), or soon 



FIG. 135. Twig of Arbor-VitBe, with its two sorts of leaves: viz. some awl-shaped, the 

 others scale-like ; the latter on the branchlets, a. 



FIG. 136. Leaf of Rod Clover : st, stipules, adhering to the base of j, the petiole : S, blade 

 of three leaflets. 



PIG. 137. PartofstemandleafofPriuce's-Feather(Polygonuni orientale) with the united 

 sheathing stipules forming a sheath. 



