94 ON AN ANOMALOUS FORM OF THE PLUM. 



hatl not been determined otherwise by the specific vital 

 energy of the plants, or of that part of the plant. 



To avoid misunderstanding, then, it will be convenient to 

 adopt the word Protophyllum, when speaking of any of the 

 elements of a bud whicli in theory might have become any 

 of the parts either of a flower or of a branch. 



The abortive plum, now under consideration, offers a 

 striking confirmation of the theory of the German poet and 

 philosopher, as we shall now proceed to state. 



The fruit or pericarp of the genus Prunus, is simple, that 

 is, the convolute Protophyllum of the ovary is single. In t''^ 

 normal form of this fruit, the exterior coloured exocarp is 

 analogous to the Hypophyllum or Epidermis^ on the lower 

 side of a leaf; the 3Iesocarp, thick and fleshy, (constituting 

 the part that is eaten), is analogous to the Mesophylhim, oi" 

 cellular tissue of a leaf; and the Endocarp, hard and long, 

 represents the Epiphyllum or Epidermis of the upper surface 

 of a leaf, thus : — 



Hypophyllum = exocarp. 

 Mesophyllum = mesocarp. 

 Epiphyllum = endocarp. 



In the anomalous fruit, now before us, each of these parts 

 has its representative, but they are in conditions widely differ- 

 ent from the normal one. Thus, the exocarp is yellow and 

 wrinkled, not smooth and red or black ; while the mesocarp 

 is as little developed as if the protophyllum had become a leaf. 

 Its cells are loose and dry, while the vessels, large and very 

 prominent, are discerned passing through it. These are seen 

 to start from the peduncle, and to divide into several sets or 

 • bundles, and to pass upwards on all sides towards the apex, 

 where the withered style is attached. The two largest sets 

 of vessels are those which run up along the inner surface of 

 the groove or suture, corresponding to the line along which 

 the edges of the protophyllum are united, and those which 

 correspond in position with the midrib in the protophyllw^- 

 These two sets, and the other smaller ones, all anastomose 



