Chapter II — 21 — Sarracenia 



2, the epidermis cells have very thick outer walls each ending in an 

 umbo, and more or less imbricated with its neighbors below (2 — 14). 

 There are numerous glands here. The appearance to the eye is vel- 

 vety, the surface being broken up by the imbrication and by the very 

 numerous, fine, downwardly directed ridges concentering on each outer 

 cell wall on the umbo. This zone forms a collar about i cm. in width. 

 While zone i is highly colored with red along the venations, green be- 

 tween, zone 2 is less colored, though the red still follows the main 

 veins. There are no stomata here. 



Zone 3 is smooth and glassy and reflects the light strongly. The 

 epidermal cells have wavy thick walls, and except for a narrow strip 

 just below zone 2, there are throughout numerous glands (I count 

 15-20 per mm 2), but no stomata. This zone occupies about one- 

 half the whole interior. Below it is zone 4, which is devoid of cuticle 

 (Batalin 1880) except for a small space surrounding the base of each 

 hair. These are numerous, downwardly pointed, long, slender and 

 glassy, and are effective in the detention of prey. The lack of cuticle 

 can be very easily demonstrated by exposing the interior surface of a 

 leaf to a weak solution of methylene blue (or other suitable dye) or 

 potassium permanganate. It shows some discoloration, being brown- 

 ish as compared with the rest of the surface. At the lower limit of 

 zone 3 the sinuous walled epidermis abruptly changes to an epidermis 

 with plain walls, and the cells appear strictly isodiametric. There are 

 neither glands nor stomata. 



For the above zones we may adopt Hooker's descriptive terms, 

 which, for zone i, is attractive, zone 2, conducting, zone 3, glandular, 

 and zone 4, detentive, even though these terms are incomplete in sig- 

 nificance. Zone I is not only attractive but is also a place of very 

 insecure foothold, because of the form and direction of the hairs. 

 Zone 2 is also both attractive because of the nectar secreted, as in 

 zone I, and affords a precarious foothold. Zone 3 has a hard, glassy 

 surface, extending the glacis of zone 2, all three zones forming a. facilis 

 descensus Averno. Zone 4 is probably not only detentive, but also 

 absorptive. 



And to these should be added a fifth zone. This is a relatively 

 narrow zone below zone 4, in which the cuticle is permanent, and 

 which is hairy only in its upper part, the lower being completely 

 smooth. There are no glands, and the epidermal cells are quite like 

 those of zone 4. Fenner (1904) calls this zone (but he was describing 

 S. flava) an absorption zone, but I think without good reason. It is 

 true that these cells do not completely resist the entrance of methyl- 

 ene blue, but this enters them much less easily than into the cells of 

 zone 4, though evidently more easily than into those of zone 3, which 

 are completely resistant. 



MacDougal recognized the zones as I have described them. 

 When subjected to total darkness, the petiolar region of the leaf elon- 

 gates greatly, while the upper zones become shorter, zones i and 2 

 showing the greatest reduction in size. Fully etiolated leaves are 

 twice the length of normal ones, but the petiolar region, including 

 the basal part of the pitcher, is five times the normal length. The 

 ventral wing does not develop, the leaf being wedge-shaped in trans- 



