72 



MORPHOLOGY OF THE CELL. 



The cells thus slightl3f separated at 

 by subsequent growth 

 bring about changes 

 in the relations of the 

 neighboring cells. 



In Sedum, as shown 

 by Strasburger, there 

 are preparatory divi- 

 sions in different di- 

 rections, 'wliile in 

 some monocotj-ledons 

 there are simultaneous 

 divisions in contigu- 

 ous epidermal cells. 



241 . Stomata are 

 not present, at least 

 in a perfect form, in any submerged 



240. As appears from 

 the following figures, the 

 first stage in the devel- 

 opment of an ordinary 

 stoma is the separation 

 of a part of an epider- 

 mal cell by means of a 

 vertical partition, thus 

 forming the mother-cell 

 of the stoma. This 

 next divides by a verti- 

 cal plane •which soon 

 exhibits a narrow chink, 

 their common wall may 



plant. In aquatics with 



63 6 



63 s 



Fig. 52. Vertical section of stoma of Hyacintlius orlentalis. (Strasburger. ) 

 Pig. 53 a, b, c. Three stages in the development of the stomata of Sedum spurlum. 

 mg. 63c shows the narrow slit maJe by the neighboring epidermal cells. (Strasburger.) 



