192 PROCEEDINGS OF THE ACADEMY OF [1893. 



It is interesting to find in Brasenia peltata, a member of the water- 

 lily family and living therefore as an aquatic under entirely 

 different conditions, similar means of protection for the younger 

 parts as observed in the case of the terrestrial plants just referred to. 



Although the chemical composition of the substances secreted by 

 means of the " Colleters " varies considerably in different land plants, 

 Hanstein applies the name " Blastocolla" indiscriminately to the 

 product. There is no reason why this name should not also apply 

 to the gelatinous coating found on the younger organs of Brasenia 

 peltata. It may be expected that a plant surrounded by air 

 requires totally different means of protection from one whose sur- 

 rounding medium is water, and it may be taken for granted that 

 the gelatinous coating of Brasenia peltata is one peculiarly adapted 

 to the conditions in which that plant lives. At present, it is impos- 

 sible for me to state the chemical composition of this substance. 

 The only point which I can state with certainty is that the princi- 

 pal constituent of the secretion is water, which fact indicates that 

 the secretion is one of those plant products which are capable of 

 imbibing great quantities of water. It must be remembered that in 

 water plants the principal water-conducting tissue, thexylem of the 

 fibro-vascular bundles, is usually reduced to a more or less extent. 

 In case of Brasenia peltata, I notice that this reduction is carried to 

 an extreme degree, the xylem being entirely obliterated in the leaf 

 petioles. There is, therefore, in this plant, no tissue particularly 

 adapted to the rapid transportation of great quantities of water. The 

 question naturally arises, how, under the circumstances here prevail- 

 ing, in a plant entirely surrounded by water, containing within no 

 xylem or water-conducting tissue, par excellence, is this imbibition 

 process accomplished? The determination of this matter is, as I 

 believe, of considerable importance, and requires a most critical 

 observation. Two methods naturally suggest themselves : the secre- 

 tion may draw the water from within, the water would then have to 

 be taken in at other points of the surface of the different parts of 

 the plant, and transferred from there to the glandular hairs ; or the 

 secretion may draw the water, or a part of it, directly from the out- 

 side. This latter, under the circumstances, seems to me the most 

 probable explanation of the phenomena here witnessed. The ques- 

 tion must, however, for the present, remain an open one. So far as 

 I know, the imbibition of water from the outside by means of gland- 

 ular hairs, has nowhere, as yet, been observed. Should the method 



