268 



OUTLINES OF PLANT LIFE. 



their defenders' wants. A very large number of species * 

 protect themselves in this way. For the ants the plants 

 provide (a) nectar, similar to that secreted in the flower 

 (i.e., a watery solution of various 

 sugars), but secreted by nectaries 

 outside the flower ; {b) fodder, in 

 the form of hairs (fig. 230), often 

 of peculiar from, richly supplied 

 with nutritive substances, grow- 

 ing from special parts of the sur- 

 face, which are regularly eaten 

 by the ants and grow again, so „., 



Fig. 230. Fig. 231. 



Fig. 230. — Bit of a section tlirough tlie cushion fc, fig. 231) at base of leaf of Gecrof'ia, 

 showing the velvety liairs with wltich it is covered, and among them the egg-like 

 bodies, rich in proteids and fats, which the ants collect and carry into their nests in 

 the interior of the stem. Magnified about 10 diam. — After Schimper. 



Fig. 231. — Apex of the hollow stem of a young Cecropia. a, the thin spot above a 

 leaf, which at b has been gnawed through by the ants to make their nests in the cavity 

 of the stem ; r, the cushion at base of leaf stalk where food bodies grow. See 

 iig. 230. Two-thirds natural size. — After Schimper. 



that a constant supply is at hand ; (e) dwellings of various 

 sorts. Certain plants have the stems hollow throughout, 

 with special modification of the structure at certain spots, so 

 that an entrance to these hollows may be readily made (fig. 



More than three thousand are listed by Delpino. 



