64 BOTANICAL GAZETTE [july 



described by Zeiller. 6 The cells are rather small, roughly 

 rectangular, and very thick- walled. The very numerous stoma ta 

 are arranged in irregular lines which give a striated appearance 



to the unmagnified specimen. 



A single stoma is shown in surface view in fig. i. The central 

 aperture is surrounded by the five "guard" cells of Berry and 

 Zeiller. A conical projection can be distinguished extending 

 from each cell to the common center and together forming the 

 rosette. These projections are really below the surface, and, since 

 they are in focus, the opening at the surface is indistinctly seen 

 above them as a pentagonal area whose walls coincide with the 

 bases of the cones. 



A clearer idea of the relation of the parts may be obtained 

 from fig. 2, which is a photograph of a vertical section through one 

 of the stomata. The conical processes of the so-called "guard" 

 cells are here seen to project into the middle of a cavity. At the 

 upper limit of this cavity, that is, at the surface, the epidermal cells 

 again approach each other to form, not conical projections, but the 

 pentagonal opening seen indistinctly in the photograph of the 

 surface. These complicated cells are regarded by both Berry and 

 Zeiller as guard cells, obviously unlike the guard cells found any- 

 where else in the plant kingdom. Zeiller compares them with 

 those of Marchantia as follows: 



Le seul fait qui me semble avoir quelque analogie avec cette constitution 

 particuliere des stomates, serait celui qu'on observe chez les Marchantiees, oil 

 les pores stomatiques sont bordes par cinq ou six cellules, mais qui laissent 

 entre elles une ouverture en forme de canal, et non pas une fente en etoile* 



comme dans l'espece dont je viens de parler. 



Lguli 



et assez peu vraisemblable que cette forme etoilee des stomates fut un fait 

 isole, n'existant que chez le seul Frenelopsis Hoheneggeri, et peut-etre faut-u 

 s'attendre a la retrouver quelque jour sur d'autres plantes fossiles, sinon meme 

 dans la nature vivante. 



In his conception of their arrangement, Berry disregards that 

 part of the cell above the diverticulum, although he figures it in his 

 low-power drawing. 7 Aside from their unique number and disposi- 



6 Zeiller, R., Elements de palaeobotanique. Paris. 1900. 



7 Loc. cit., p. 307. 



