MARGIN AND APEX. 



27 



like a saw, with the teeth projecting forward. Such a mar- 

 gin is said to be serrate, or, if the teeth are quite small, ser- 

 rulate. "When the teeth point neither forward nor back- 

 ward, but outward, we call the margin dentate, or toothed ; 

 and if the teeth are quite small, denticulate. See Figs. 49, 

 50, 51, <fec. 



31. Some leaves are margined with rounded and blunt 

 teeth, and we call them crenate (Fig. 52) ; or, if such teeth 

 are very small, crenulate. 



32. In Figs. 13 and 50, you see that the teeth themselves 

 are again toothed, an arrangement called doubly serrate, 

 So we may find leaves doubly dentate or doubly crenate. 

 Thus we have described seven modes or styles of border- 

 ing. Several other modes are found described in the larger 



botanies. 



APEX. 

 abode/ 



Fiy. 56. Apex of leaves : a, obcordate ; i, emarginate ; c, retnse ; d, truncate j 

 e, obtuse ; y, acute ; g, mucronate ; A, cuspidate ; k, acuminate. 



Fig. 57. Bases of leaves: I, hastate; wt, w, sagittate; 0, auriculato; p, cordate; 

 7, reriform. 



SO When is the margin serrate ? When serrulate ? How ioes the den 

 tale differ from the serrate ? 



31. What sort of teeth does the crenate imply ? Crenulate ? 



32. Explain doubly dentaie, &c. 



