104 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



of Nepenthes does actually produce a digestive enzyme, and 

 that there is no ground for attributing the digestion of proteids 

 which undoubtedly occurs in the pitchers, to the action of 

 micro-organisms. 



In concluding the consideration of Nepenthes, I must briefly 

 allude to the mechanism of the secretion. In many cases, as is 

 well known, the secretion of liquid by leaves is dependent upon 

 the root-pressure, ceasing directly the leaf is detached from the 

 plant. As Wunschmann first definitely proved (" Die Gattung 

 Nepenthes," 1872), this is not the case in Nepenthes ; the 

 pitchers continue to secrete for some days after they have been 

 detached, provided that the cut ends of their stalks are placed 

 in water. In this respect the pitchers of Nepenthes resemble 

 nectaries. 



On account of the similarity of its pitchers to those of 

 Sarracenia and Nepenthes, Cephalotus may be conveniently con- 

 sidered next. Unfortunately our knowledge in this case is far 

 less complete than in the two preceding cases. In his paper 

 on the Botany of Terra Australis, Robert Brown states that 

 " the ascidia or pitchers of Cephalotus were observed to be in 

 general nearly half filled with a watery fluid, in which great 

 numbers of a small species of ant were frequently found 

 drowned. This fluid, which had a slightly sweet taste, may 

 possibly be in part a secretion of the pitcher itself, but more 

 probably consists merely of rainwater received and preserved 

 in it." However, there is now no doubt that the liquid is, at 

 any rate for the most part, really secreted ; for, as Goebel points 

 out (" Pflanzenbiologische Schilderungen," II., p. Ill), unopened 

 pitchers contain liquid. As regards the structure of the internal 

 surface of the pitcher, the under surface of the lid is smooth 

 and slippery, as is also the inner surface of the thickened 

 margin (or " collar ") of the orifice ; the surface of the middle 

 portion of the pitcher bears numerous glands, which do not, 

 however, appear to be digestive glands ; and within this region 

 there are two lateral projecting areas which not only bear 

 glands, but numerous water-pores in addition ; the lower part 

 of the pitcher has no glands. What the glands secrete is not 

 clearly ascertained, though it may be honey ; probably the 

 liquid in the pitcher is secreted through the water-pores. In 

 view of these peculiarities of structure of the pitcher, there can 



