148 



THE FACTORS 



[Part 



and occupies only the upper half of the intcrnode in which it occur 

 so that the principle of providing resistance to bending is no longc 

 applicable. 



Whether Humboldtia laurifolia belongs to the last-mentioned type c 

 to that of Triplaris, I must leave undecided. In this case numeroi 

 bright red nectaries are present on the leaves and stipules. 



Cordia nodosa (Fig. 84), of which I was able to observe numerov 

 specimens growing wild at Pernambuco, belongs to still another typ 

 Here the long inferior internode of the flowering shoot, which in i 

 upper part forms a condensed tuft, bears, immediately below the leav 

 and inflorescence, a lateral bladder into which a little pre-existing openir 



Fig. S4. Cordia nodosa. P'alse whorl with inflorescence-axis and bladders. 

 One-half natural size. 



leads between the petioles. I found the bladder always occupied 

 minute ants. Here the connexion between the dwelling-place of t 

 ants and the flowers is very clearly exhibited, and the same feati 

 is repeated in numerous other cases, for example in the lauraceci 

 Pleurothyrium macranthum, where only the axes of the inflorescer 

 are hollow and inhabited by ants. 



The famed myrmecophj'tcs of the Malayan Archipelago, species 

 Myrmecodia and Hydnophytum (Figs. 85 and 86), exhibit a type 

 axial chamber quite different from the foregoing ones. Here it is ' 

 longer a case of a single central chamber in a cylindrical wood)' intcrnoj-, 

 but of numerous sponge-like communicating spaces in a succulent tuhi', 

 which, since the plants in question are epiphytes, possibly in the fi' 

 place serve as a water-reservoir. The water is stored in the parenchyi|i 



