BY ALEX. G. HAMILTON. 787 



stomata were contained in crypts in which they were sheltered 

 from excessive transpiration by long hairs, and that under altered 

 climatic and other conditions the stomata passed out to the 

 general surface, leaving the pits as relics of the former state of 

 affairs. I made a careful examination of several species of 

 Banksia and of Nerium, but found the crypts of a totally different 

 character, and in addition, in both genera, the crypts are evenly 

 scattered all over the surface, while in the species under con- 

 sideration they occur only in the axils of the veins, or rarely (f.g.., 

 Pennantia) on the course of the veins and appear to have a 

 definite relation to those organs. 



Again, the solution was offered that they might be extra 

 growths caused by the superabundance of sap at the axils. But 

 the fact that they ai^e found mostly in the middle axils on the 

 midrib, and not on the lower ones, where the sap would naturally 

 be more plentiful, bears against this, and their regular organisa- 

 tion and appearance I think sufficiently negatives this theory. 



The purpose which seemed to me most feasible, and which I 

 took most pains in working out, was that they might perhaps be 

 organs for absorbing gas, vapour or water, and this seemed all the 

 more likely from the fact that the plants possessing them are all 

 inhabitants of moist climates. New Zealand, Norfolk and Lord 

 Howe Islands being their head quarters. Careful experiment 

 showed that they would not fill when the leaf was wetted, the 

 small opening being stopped by an air bubble, nor could I, even 

 by prolonged submersion, succeed in filling them. To be sure I 

 was not mistaken, I tried an alcoholic stain (as it flowed freely 

 and would leave the epidermis stained as a record) and even 

 mopped the cavities out with alcohol to encourage capillary action, 

 but still the liquid would not run in. Mr. Betche tells me he 

 succeeded in filling the pouches of Dysoxylum Fraseriamim by 

 immersion for some hours, and he thinks the fact that dust is often 

 found inside is an additional proof that rain does run in and 

 carries with it foreign matter. Their position on the under side 

 of the leaf, too, is to some extent unfavourable for their filling, so 

 that on the whole I had to abandon the hypothesis. I- also tried 



