CHAP. I. THE LEAF. 55 



the varieties of its form, of which they generally 

 enumerate upwards of an hundred. 



If the expansion is flat and membranaceous, the 

 most frequent forms are the circular, the oval, the 

 oblong, the triangular, the rhomboidal, the lanceo- 

 late, the tongue-shaped, the lyre-shaped. If they 

 are thick and succulent, the most frequent forms are 

 the cylindrical, the semi-cylindrical, the tubular, 

 the sword-shaped, the compressed, that is thick and 

 fleshy in the middle but flattened at the edges. 

 The apex is very generally acute or pointed, but it 

 is often also obtuse and sometimes appearing as if 

 bitten or truncated., as in the leaves of Epidendrum 

 pramorsum and the Tulip-tree. (PL II. Fig. 8.) 

 The margin is entire, or cartilaginous, or undulated, 

 or curled, or notched, or toothed, or serrated, or 

 fringed, that is cut into fine and small segments, or 

 set with strong hairs. But if the segments are 

 large the figure of the expansion is more varied. 

 Sometimes it is simply cleft, sometimes wing-cleft, 

 sometimes lobed, and at other times it has the ap- 

 pearance of being torn or jagged, as in the leaf of 

 Senecio squalidus. (PL II. Fig. 7.) But the figure 

 of some leaves is altogether anomalous, and cannot 

 be brought under any of the foregoing divisions, 

 nor indeed under any other divisions that botanists 

 have yet instituted, such as those of Nepenthes 

 distillatoria (PL II. Fig. p.), Sarracenia purpurea 

 or Purple Side-saddle-flower (PL II. Fig. 10.), and 

 Dioncea Mucipula or Venus's Flytrap (PL II. 



