©vtgtnal 'Mxtitlt^. 



ON THE STRUCTURE OF THE PITCHER OF 



CEPHALOTUS FOLLICULARIS. 



By Alexander Dickson, M.D., Eegius Professor of Botany in the 

 University of Glasgow. 



(Tab. 193.) 



[Abstract of a paper read at the meeting of the British Association at 

 Plymouth, August, 1877.] 



In Cephalotiis there are two forms of leaf : — 



1st. Xon-ascidiform, v/ith petiole and lamina of ordinary 

 description; and 



2ncl. Ascidiform, with cylindrical petiole, from extremity of 

 which depends a jpitcher, with a lid attached by a broad base to 

 that part of the orifice next the petiole and the main axis. The 

 pitcher here appears to be a pouching from the under surface of 

 the leaf, in this respect differing remarkably from those of 

 Nepenthes and Sarracenia. It is scarcely safe, in absence of 

 developmental evidence, to dogmatise on the subject ; but, as 

 matter of fact, the pitcher-lid in Nepenthes and Sarracenia springs 

 from that portion of the orifice farthest from the axis ; while in 

 Cephalotus, as above stated, it springs from that portion next the 

 axis. In Nepenthes, Sir J. D. Hooker has shown that the leaf-apex 

 is represented by a bristle-like process at the back of the hinge of 

 the lid (Fig. 2, ap). In Sarracenia the lid itself would appear 

 to be the terminal lobe of the leaf. In Cephalotus, also, it seems 

 sc9.rcely possible to doubt that the lid represents the terminal 

 lobe of the leaf, and, if so, the pouching, as already said, must be 

 from the lower leaf- surface. The Cephalotus pitcher exhibits on 

 its outer surface three w^ll-marked wing-like processes, one median 

 (Fig. 1, mdw) placed dorsally (away from the axis), and two lateral 

 directed obliquely. The lid (Fig. 1, /) of the pitcher is somewhat 

 concave towards its inner surface, and exhibits strongly-marked 

 ribs branching dichotomously, and connected by transverse 

 smaller veins. It is usually more or less streaked with red, and 

 tovrards the margin are to be seen, in the areolae between the 

 veins, translucent spots where the parenchyma is deficient, and 

 which remind one of those on the upper part of the pitcher of 

 Darlingtonia. From the outer surface of the lid, from the wing- 

 like ridges, and also from the margins and petioles of the non- 

 ascidiform leaves, more or less elongated pale brown hairs spring 

 of very remarkable structure. The orifice of the pitcher is furnished 

 with a cartilaginous corrugated rim produced internally into a 

 n. s. vol. 7. [January, 1878.] u 



