HISTOLOGY OF PITCHER PLANTS. 159 



colour is discharged from a portion of the plant by means of alcohol, 

 they are at once apparent, and their contents are seen to be different 

 from that of the surrounding cells, the chlorophyl corpuscles being 

 absent. These I take to be glands, but what their function may be, 

 if any, is rather difficult to imagine. 



In this plant also Dr. Tait failed to find any evidence of a true 

 digestion. 



Our next species is Cephalotus folliailaris, (he smallest, but one 

 of the most interesting of the group. It has two forms of leaves — 

 ordinary unaltered foliage leaves and ascidiform leaves or pitchers. 



An account of tlie structure of the latter was given by Dr. Dick- 

 son in the " Journal of Botany " for January, 1878, with which I 

 agree in all particulars. For a general description, therefore, of the 

 pitcher I would refer you to his paper. While, however, he de- 

 scribes the various forms of glands possessed by the plant, he does 

 not figure them, neither does he in either case give certain details 

 which I am now able to supply. 



Cephalotus possesses no less than four forms of glands, one of 

 which (Fig. 11) is to be found alike on both surfaces of the un- 

 altered leaves and on the outside and upper portion of the inside of 

 the pitcher, the other three forms (Figs. 8-10) being confined to 

 the secreting and absorbing surfaces of the interior. 



Dr. Tait, in speaking of the unaltered leaves, says : — " Beside 

 [stomata] there are papillary prominences with deep crypt-like 

 cavities. In a young leaf the occurrence of transition forms between 

 these craters and the stomata make it certain that they are deve- 

 loped from the latter, and ought, therefore, to be regarded as respi- 

 ratory organs. We might call them tracheoles, for stomata are 

 sometimes visible within them." 



Now, the only organs beside the stomata which are to be found on 

 the unaltered leaves are the glands shown in Fig. 11, which are 

 thus described by Dr. Dickson when treating of the exterior of 

 pitcher and lid — " Here occur stomata of ordinary type and 

 peculiar glands, each consisting of a group of small cells. Each 

 group as viewed from the surface is of oval form, two cells forming 

 a central oval, with their line of contact across the short diameter, 

 these two cells being surrounded by four others. Similar six- 

 celled glands are to be found on the inner surface of the pitcher lid, 

 on the corrugated rim of the pitcher, and on both surfaces of the 

 nonascidiform leaves." 



