278 



CZEKA.NOWSKIA. 



frequently peels off the surface of tte rock, and may be readily 

 cleared for microscopical examination by means of Schulze's 

 macerating solution. Several pieces of leaf have been prepared in 

 this way, and in some instances rendered more distinct by staining 

 with safranin ; the outlines of the epidermal cells stand out clearly, 

 and rows of stomata, with oval guard-cells, extend along the 

 length of the needles. 



The form of the cells is shown in the small piece of cuticle 

 represented in Fig. 48 ; the fragment is not large enough to 

 demonstrate the occurrence of numerous stomata in rows, but if 

 a strip of leaf be carefully prepared and mounted, the manner of 

 occurrence of the guard-cells is at once apparent. In the majority 



Fig. 48.' — Part of tlie epidermis of Czehmowskia Murrayaiia (L. & H.), 

 showing stomata. 



of the species of Isoetes there are very few or no stomata, but in 

 the land-forms, /. Bwimi, Bory, and /. Eystrix, Bory, stomata are 

 abundant.' An. examination of a leaf of the latter species reveals- 

 about four rows of stomata which occur over two large air-spaces ; 

 but the resemblance of the epidermal cells to those of Solenites is- 

 much less strikiiig than in the case of coniferous needles. I have 

 no hesitation in expressing the opinion that the structm-e of these 

 Jurassic leaves agi-ees most closely with that of the needles of 

 recent Conifers, and affords confirmatory e-^idence in favour of 

 classing Solenites or C%ekanowslda among the Coniferee. The 

 examination of the epidermal cells of Solenites ( C%ehmowshia) led 



Baker (87), p. 124. 



