172 Professor Dickson on the 



seems to be that in May the trees are only developing 

 their leaves, without which wood cannot be formed ; and 

 that in September they are busy forming their buds for 

 next spring, and also ripening their new wood. More 

 extensive observations are necessary for settling the relative 

 rate of growth in tlie several months. Already, however, 

 the table gives an indication that June and July are the 

 most favourable. 



The only other general conclusion to be drawn from the 

 table is that evergeen trees })egin to increase in girth 

 a month earlier than leaf-shedding trees — a fact which is 

 intelligible enough, as they have leaves ready to make use 

 of the sap at its first rise. It is not so easy to understand 

 why most of these made the subject of observation added 

 little, or even nothing, during the month of August, when 

 the weather was invariably fine. 



On the Morjpliology of the Pitcher of Cephalotus folliculans. 

 By Alexander Dickson, M.D., Professor of Botany 

 in the University of Edinburgh. (Plates V. and VI.). 



In a paper on the Structure of the Pitcher of Oephcdotus 

 follicularis, read at the Plymouth meeting of the British 

 Association, and published in the "Journal of Botany" in 

 January 1878, I pointed out the remarkable difference as 

 to the position of the lid of the pitcher between Cephalotus, 

 on the one hand, and Sarracenia and Nepenthes, on the 

 other. In Cephalotus the lid is placed on that side of the 

 orifice of the pitcher nearest to the main axis, while in 

 Sarracenia and Nepenthes it is on the side farthest from 

 the main axis. At that time I was inclined to assume 

 that the pitcher-lid in Cephalotus represented the extremity 

 of the leaf, and this led me to suggest — although under 

 reserve — that, while the pitcher in Sa^Tacenia and 

 Nepenthes appears as a pouching of the leaf from the upper 

 surface, in Cephalotus., on the other hand, the pouching 

 would, on the assumption indicated, be from the lower 

 leaf-surface. Developmental evidence is at present scarcely 

 attainable, requiring, as it would do, the sacrifice of many 

 specimens of a plant not very easy of cultivation, and never 



