182 M. Miiller on the Germination o/Isoetes lacustris. 



first becomes distinctly visible in the stages just preceding the 

 breaking-through of the ovule (PL II. fig. 15 c). It here lies close 

 to the matrix of the root (fig. 15 /), which at this period it wholly 

 resembles in shape. Each of these constitutes one-half of the 

 germinal body, the matrix of the root that one on which the 

 vagina of the leaf-bud occurs, the alimentary organ the opposite. 

 Upon the two rests the first leaf, so that the vagina is pushed a 

 little to one side. 



The alimentary organ is composed of very small, parenchy- 

 matous cells, which are so densely filled with granular contents 

 that the organ is clearly defined, in contrast with the matrix of 

 the root, as a darker-coloured body. The manner in which this 

 kind of cell-contents is restricted to the cells of one-half of the 

 germinal body is exceedingly striking. This matter takes a deep 

 blue colour with iodine, and thus clearly displays its amylaceous 

 nature. By means of this reagent also we find that the amylum 

 has not been deposited all at once in this region. Even in much 

 earlier stages, for instance in fig. 11 a, the formation of it has 

 commenced, and it continues gradually from that time till the 

 alimentary organ is perceptible as an independent part of the 

 germinal body. 



Amylum-cells are indeed found in very early stages in other 

 parts of the embryo, for example in fig. 11 oid also ; but at this 

 point they become rapidly absorbed and applied to the further 

 development of the embryo. As for the rest, the amylum origi- 

 nates from one and the same matrix in all parts of the plant, 

 namely from the cytoblast. This is but a new confirmation of the 

 observations which I had an opportunity of making formerly in 

 Char a crinita^, and which have been confirmed by English bo- 

 tanists, especially by Quekettf. It here appears that single cy- 

 toblasts become decomposed into many starch granules (PL II. 

 fig. 17 f, PL III. figs. l%d, 20/, 21 c), since in those cells where 

 the starch granules occur, the cytoblasts have wholly disap- 

 peared, and yet no other matter is present. This agrees also 

 with the formation of chlorophylle ; for in those cells where this 

 occurs, nothing but cytoblasts are to be found at an earlier 

 period. These suddenly vanish and a quantity of granules ap- 

 pear in their place, which at first acquire a blue colour with iodine, 

 and consequently have been transformed into starch; subsequently 

 they become perfectly green. 



By degrees, accompanying strictly the gradual development of 

 the germinal body, the starch of the alimentary body undergoes 



* Bot. Zeitung, 1845, p. 833, " Einige Bemerkungen iiber die Bildung 

 des Amylums." (Remarks on the Formation of Starch.) 



t Bot. Zeit. 1816, p. 707 (from the Annals of Natural History, Series 1. 

 vol. xviii. p. 193). 



