THE STRUCTURES OF PITCHER PLANTS. 



section very much resemble those of the solitary glands of 

 intestine. They vary in size, even in the mature pitcher, from 

 that of the multifid bud on the outside (-05 mm.) to a size which rivals 

 that of the largest glands in Nepenthes, (-275 mm.,) and are then quite 

 visible to the naked eye. These largest glands are situated on two 

 eminences, composed of a thickening of the parenchyma, situated 

 obliquely, near the bottom of the pitcher, and symmetrically, one on 

 either side. These glandular bodies are crescentiform, and measure 

 about 11mm. by 3. The smaller glands are distributed very irregularly 

 over the surface of the pitcher, but each gland, whatever its size, seems 

 to have a close relation to a twig of spiral tissue with which the pitcher 

 is very liberally supplied. The glands are composed of polygonal cells, 

 between which run intercellular canals. I have never been able to trace 

 any direct connection between the glands and the spiral tissue. On the 

 inner surface of the lid the cells are spiked and point inwards, and the 

 multifid buds exist just as in the Sarracenia. In a completely formed 

 pitcher, which still had the lid adherent to the lip, I found a few drops 

 of clear and slightly viscid fluid, perfectly neutral, and containing two 

 substances, to which I have given the names of Droserin and Azerin, 

 described elsewhere, together with traces of chloride of potash and 

 soda. In two pitchers I found insects bathed in fluid, with a strongly 

 acid reaction, and this fluid digested shreds of albumen exactly as I 

 found the fluid of Nepenthes pitchers did. I conclude, therefore, that a 

 true digestion of its victims is carried on by the Cephalotus pitcher. 



NEPENTHES. 



In this family I have been able to examine a large number of 

 pitchers from the following varieties: — N. distillatoria, ampullacea, 

 ampullacea vittata, hybrida, hybrida maculata, lanata, Rafflesiana, 

 phyllamphora, gracilis, levis, Hookeri, Sedeni, Khasyoma, and sanguined. 



I have made a large number of observations on their gland 

 structure and its functions, but they may be all liable to correction, as 

 I have not yet had an opportunity of examining native-grown pitchers. 

 The discrepancies which I have met with are very few, and being 

 confined entirely to minor details of the quality and action of the 

 secretion of the pitchers, I do not attach much importance to them. 

 Still I feel certain that these interesting structures must be studied 

 each in its native place before our knowledge of them is complete. 



The form of the pitchers is too well known to need description. 

 On their outer surfaces two ridges occur very constantly, which, in 

 some varieties (Rafflesiana and Veitchii) reach to a large size, and are 

 deeply fringed at the margins. They extend from the base of the 

 pitcher in an angle from the stalk up to the lip, and include a space 

 which I propose to call the platform. In such pitchers as have these 

 wings there is a constant tendency for the stalk of the pitcher to rest 

 in contact with the platform, and I have watched plants and seen that 

 this is of essential service to them in procuring insect food. 



This particular kind of nutrition seems to be most necessary for 

 the plants during their youth, for as those which have winged pitchers 

 grow old they tend to produce pitchers without wings, with other 

 changes in their structure, and with very much impaired digestive powers. 



Thus the pitchers of N. Rafflesiana in a young plant are flask- 

 shaped, the largest diameter being near the bottom, the wings are 



