Francis E. Lloyd — 122 — Carnivorous Plants 



tion as an endodermis, though Fenner questions Goebel's view that 

 water may pass only in one direction (outwardly). The outer ends of 

 these cells form a continuous single row of rounded outHnes like a string 

 of beads, seen in an entire gland, which limits the gland proper from the 

 uppermost transverse course of stalk cells. These cells were seen by 

 Warming, whose drawing Darwin reproduces. But Darwin (1875 

 2d. ed., p. 5) himself failed to see them, nor, said he, did Nitschke, 

 though one of his drawings seems to indicate that he did. Neither 

 did Gronland (1855) or Trecul (1855) see them. 



Fitting over the parenchyma bell are the two layers of glandular 

 cells. The outer course is made up of columnar epidermal cells, 

 polygonal en face, their outer ends covered by a cuticle and their 

 radial, and sometimes outer walls strengthened by cellulose buttresses 

 and beams (75 — 13), as shown by Fenner. They are most pro- 

 nounced throughout the lateral reaches of the gland and diminish in 

 stature toward its apex, from which they are quite absent (Huie), 

 though Homes thinks they occur here, but are smaller, in much smaller 

 numbers and far apart (1928). Careful examination persuades me to 

 agree with Huie. They are obvious in the apical cells of the glands 

 of D. pygmaea. Naturally enough, the protoplasm of the cell fits into 

 the bays between the buttresses, and by the use of weak H2SO4 for 

 maceration, the protoplasts may be isolated and are then seen edged 

 with crenellations, interpreted by Haberlandt as sensitive papillae. 

 If this is a correct view, we must think that the glands are more sensi- 

 tive along their sides than on the apex, for which we have no evidence 

 one way or another. 



The cuticle covers over the whole of the gland and is continuous 

 with that of the stalk. As Huie has said, it is quite continuous and is 

 not penetrated by pores (Gardiner) nor is it absent from the apical 

 cells (Goebel). Goebel's statement to this effect appears to have 

 been due to the observation of the earlier penetration of solutes through 

 these cells, but I have satisfied myself that methylene blue enters 

 equally rapidly over the entire surface of the gland. Prolonged treat- 

 ment with sulphuric acid leaves a very delicate continuous membrane 

 covering it. Yet as Huie says, the cuticle is readily penetrated by 

 silver nitrate, just as by methylene blue. Another observation of 

 Huie's I can confirm, namely, that in life the lateral walls of the 

 apical cells are often separated from each other by fissures tapering 

 inwardly between them, as if the walls had separated along the middle 

 fine. It is possible that this is what Franca saw in Drosophyllum, 

 interpreted by him as canals leading to the inner course of glandular 

 cells. The nucleus of these cells lies near the base and the cytoplasm 

 has a large vacuole in the outer moiety of the cell (in the resting con- 

 dition — see beyond under aggregation). 



The second layer of glandular cells lies between the epidermis and 

 the parenchyma bell, and is composed of more depressed and irregular 

 cells, overlooked by Nitschke, but seen by Darwin, and correctly 

 described by Warming. The cells are irregular in shape fitting the 

 irregular bases of the epidermal cells without intercellular spaces. 

 The functions of these two glandular layers differ according to Homes 

 as we shall see. 



