202 LINARIA CYMBALARIA. 



organs. The figures 9, 10, and 11, were drawn by the aid of 

 the neutral-tint reflector. In sections of the leaves mounted in 

 balsam, the interior cells are readily seen. The upper cuticle 

 covers the usual perpendicular cells, filled with dense masses of 

 chlorophyll ; the under cuticle encloses cells comparatively free 

 from this deposit, and although the stomata are indistinct, the air- 

 cells in connection with them are easily traced. I cannot detect 

 starch-grains or crystals, but as these sections polarise well, they 

 may probably contain both. 



I have already entered somewhat fully into particulars of the 

 component parts of the flower-stem of this Linaria^ but I will 

 dwell for a moment upon the Plant-Stem. It consists of an 

 outer cuticle, highly coloured by the matter formed within its large 

 transparent cells, and contains but little chlorophyll. The inner 

 cuticle or membrane is composed of denser cells, with an abund- 

 ance of green matter. The interior portion is composed of a 

 central medulla or pith, a cellular formation of larger cells than in 

 other parts of the stem, and giving in a transverse section the 

 characteristic of a hollow stem. Immediately surrounding the 

 pith comes the medullary sheath of spiral vessels ; then a zone of 

 denser cells, surrounded by a mass of larger cellular tissue, while 

 the cuticle encloses all. 



The Roots of this little plant are remarkable for their clinging 

 powers. This is not to be wondered at when we consider the 

 position which the whole plant occupies on perpendicular walls. 

 It has the means, by its fibrous roots, to adhere to its otherwise 

 precarious lodging. 



In conclusion, let me remark on the desirability of making 

 common objects our study. Take any object you please, 

 and endeavour to bring it into monographic description, and 

 you will have an interesting subject of investigation. This 

 little Li/iaria, as I gaze upon its festoons, reminds me of many 

 happy hours spent in its cheerful company, and we shall ever be 

 familiar friends. Sir John Lubbock, in closing one of his books, 

 writes : — " Few, I believe, of those who are not specially devoted 

 to zoology and botany have any idea how much still remains to be 

 ascertained with reference to even the commonest and most 

 abundant species."' 



