294 Linnean Society. [April 21, 



on the growth of starch in the leaves of Vallisneria spiralis. Miiller, 

 he states, has observed that in the cells of Chara crinita, the cyto- 

 blast becomes hoUow, enlarges, and fiUs the cell-membrane in which 

 it is contained, and ultimately becomes the reservoir for granules of 

 starch ; while Nageli has observed that in Caulerpa prolifera, at the 

 period of the formation of starch, the cells contain several smaller 

 cells, in each of which are developed generally from three to four 

 grains of starch. In order to observe the growth of starch and chlo- 

 rophylle, Mr. Quekett examined in several plants the organs in which 

 those substances are generally situated, and found that their forma- 

 tion took place, in the majority of instances, in the following manner. 



In the very young stem of Circaa Lutetiana, or the young branch 

 of the Grape- Vine, the different appearances presented by the grains 

 of starch from their perfect state down to their first commencement 

 may be readily observed by making numerous sections from the 

 lowermost internode up to the terminal joint. The cells most re- 

 cently formed are so filled with mucilage and granules as to be opake ; 

 lower down the granules begin to disappear and the cytoblast is ap- 

 parent ; still lower the cytoblast appears to have lost its granular • 

 character without having much increased in size, and has become a 

 minute cell with a distinct nucleus, instead of a congeries of gra- 

 nules with a larger central one. On the outside of this nucleated 

 cell, granules (varying in number from ten to twenty) make their 

 appearance, at first very minute and of a green hue, and afterwards 

 enlarging and becoming colourless ; and as they increase in size the 

 nucleated cell is absorbed and the granules become free. At a later 

 period a multiplication of the granules takes place by fission and 

 pullulation, certain grains exhibiting marks of subdivision, and 

 others having minute granules attached to them ; and generally 

 more grains of starch are found in a cell than the number of minute 

 granules seen developing on the nucleus. 



Several of these stages are more readily seen in the tuber of the 

 Potato. If a slice be removed from its exterior so thin as only to 

 pass beneath the cuticle, and a very thin and perfectly transparent 

 slice be then taken and examined under the microscope, the cells in 

 the central portion are seen to contain only a few grains of starch, 

 while in approaching the sides of the section the grains become 

 smaller and pass gradually into the nature of chlorophylle. On di- 

 recting attention to those parts of the section, in which the cell- 

 contents pass gradually from the state of starch to that of chloro- 

 phylle, many cells are seen to contain a distinct nucleated cell, ap- 

 parently of a flattened or lenticular form, on the edge of which are 



