198 



PRINCIPLES OF PLANT-TERATOLOGY. 



(PI. XIX, fig. 1). Sometimes, as in leaves of some 

 Phlox paniculata which had been attacked by eel-worm 

 at the roots, the small, flat basal portion of the leaf 

 bore on its lower surface, not a pitcher, but a long, 

 naked piece of midrib, though in some leaves this had 

 developed a slender strip of blade (PI. XIX, fig. 2). 



In other plants the outgrowth from the lower surface 

 may arise a short distance from the apex as a continua- 

 tion of the midrib ; and this extension of the midrib 

 may or may not expand at its end into a more or less 

 hollowed lamina. There is a variety of " croton " 

 (Codiseum variegatum) which exhibits this phenomenon 

 (PL XVII, fig. 1).* 



It is very interesting to find the same thing precisely 

 occurring in the ferns, e. g. in certain varieties of 

 Seolopendrium vnlgare, viz. cornutum and peraferum, 

 where the midrib often merely assumes the form of a 

 thorn-like body projecting from the upper or lower 

 surface. 



Now, this very phenomenon which we find so 

 frequently in a diversity of plant-groups as a " sport," 

 occurs as a perfectly fixed and normal character in the 

 pitcher-plant (Nepenthes), every leaf in all species pro- 

 ducing stalked pitchers representing an extension and 

 expansion of the midrib ; in most species, however, the 

 extension occurs from the actual and extreme tip of 

 the leaf, as is often also the case in Codideum, but in 

 others it is distinctly from the lower surface a very 

 short distance behind the actual apex ; Eichler was 

 mistaken in stating that this latter phenomenon does 

 not occur in Nepenthes. 



b. Ascidia of the Entire Leaf. — In the first place 

 must be mentioned the case of a cabbage in which was 

 observed such a pitcher consisting of the entire leaf : 

 in this case the inner surface of the pitcher was 

 morphologically the lower (PI. XV, fig. 3), and in this 

 respect it exactly resembles the extraordinary leaf- 

 formation in " Fie as Krishna ," a form of Ficus bengha- 



* See Celakovsky's beautiful illustrations of this form. 



