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 tlie teeth are quite small, denticulate. See Figs. 49, 

 50, 51, &c. 



31. Some leaves are maro^ined 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 douUy dentate. 

 So we may find leaves doubly serrate or doubly crenate. 

 Thus we liave described seven modes or styles of border- 



ing- 



Several other modes are found described in the larsfer 



botanies. 



56 



APEX. 



57 



Flff. 56. Apex of leaves: or, obcordate ; 6, emarginate; c, retuso ; rf, truncate ; 

 «, obtuse ; f, acute ; ^, mucronate ; h, cuspidate ; k, acuminate. 



Fig. 57. Bases of leaves: I, hastate; m, w, sagittate; o, auriculate ; p, cordate; 

 7, rcniform. 



30. When is the margin serrate ? Wlien serrulate ? How ioes the den 

 tate differ from the serrate ? 



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

 33. Explain doubly dentate, &c. 



