Chapter I — 15 — HeUamphora 



The walls of these cells which lie in contact with those of the 

 gland immediately above (if we assume an orientation of up and 

 down, the cover cells being up) are always strengthened by curved 

 thickenings like those of xylem vessels. Krafft seems to have re- 

 garded these cells also to be cuticularized, and the wall thickenings 

 to be on the lateral walls in contact with surrounding parenchyma 

 cells. On both these points he was mistaken. The wall thickenings 

 are found on the walls only where the cells impinge on the gland cells, 

 and are not cuticularized in any part. This arrangement is found also 

 in the glands of Sarracenia, as Goebel showed, to be described be- 

 yond. The function of these parenchyma cells is not known, but it 

 serves to call them transmitting cells. But whether they do more 

 than permit movement of substances from the leaf tissues to the 

 gland, is not known. There is no reason to particularize as to the 

 distinction between the glands of the inner and outer surfaces, be- 

 yond the fact that where the outer surface glands impinge on the 

 underlying parenchyma, the parenchyma cells in immediate contact 

 are sometimes so large that it is very easy to recognize the fact that 

 the wall thickenings occur only where the gland cells are in contact 

 with the parenchyma cells. In cases where the section has run through 

 the gland at right angles to the common axis of the contingent pa- 

 renchyma walls beneath the gland, it becomes apparent why cell 

 walls carrying the thickenings appear to be other than those exactly 

 in contact with the glands, namely, because of the oblique position. 

 In making a drawing one is usually forced to show them as if they 

 were anticHnal, instead of periclinal walls. For this reason one can 

 understand how Krafft may have been misled. Viewing the gland 

 from beneath, possible in tangential sections, leaves no doubt about 



the facts. 



The glandular cells and the contingent parenchyma cells were 

 regarded together as constituting the gland by Krafft, and the 

 whole was attributed by him to an epidermal origin. But the pa- 

 renchyma cells are certainly not of glandular nature, judging by their 

 meagre protoplasmic contents, and are of equal certainty not of epider- 

 mal origin. One hardly needs to see developmental stages to draw 

 this conclusion. Tenner's account of the origin of the Sarracenia 

 nectar gland, which is of the same structure as that of HeUamphora, 

 also includes the parenchyma cells. 



The large glands are found only on the inner surface of the spoon. 

 Krafft correctly traces this type of gland to an epidermal origin, 

 but does not show that in this gland also there are to be found the 

 xylem-Hke parenchyma cells. He attributes to the gland an identity 

 with the large glands found in Cephalotus which, as we shall see when 

 we discuss the latter, is not justified. These glands occur to the 

 number of about 20, larger and smaller in size, the larger ones being 

 in a more lateral position. And these are very large. In surface 

 view they consist of a number of cover cells and first course cells, 

 underlain by about four courses of thick walled cells beneath which 

 lies the mass of glandular cells proper. The periphery of this mass 

 is irregular, as if there was a tendency of the glandular mass to branch 

 or lobe. The contingent parenchyma by the same token intrudes 



