36 



MORPHOLOGY 



ends in an abrupt point, as in the leaflets of many 

 Cassia (kalkasonda); and cuspidate when the acute 

 apex is spiny, as in Pine-apple (anaras) and Pan- 

 danus (kia). 



In a sessile leaf the base of the blade may be pro- 

 longed into two ear-like lobes, which partially or 

 wholly clasp the stem. Such leaves are called auricu- 

 LATE (fig. 33) or AMPLEXiCAUL (fig. 34), according as 

 the clasping is partial or com- 

 plete. If the two lobes be united 



Fig. 33. — Auriculate 

 Leaf 



Fig. 34. — Amplexicaul 

 Leaf 



Fig. 35. — Perfoliate 

 Leaf 



together on the side of the stem opposite to the in- 

 sertion of the leaf, the leaf is said to be perfoliate 

 (fig. 35). If two opposite auriculate leaves unite by 

 the lobes of their bases so that the stem seems to pass 

 through the middle of the united blades, the leaves 

 are said to be connate (see fig. 211). 



If a blade be examined, it is found that the soft 

 structure of it is traversed by stiff threads, which are 

 called VEINS or ribs or nerves (see fig. 33). The 

 arrangement of veins in a blade is termed venation. 

 The venation is classified into four types, namely: 

 pinni-veined, palmi-veined, parallel-veined, and 



