M. Miller on the Development of Chara. 327 
as the external cells are transformed into branches and shoots. 
The cortical layer is thus attached in its very earliest stage, sub- 
sequently attaining very great strength, and is readily separable 
from the central utricle. The intercellular spaces which are 
formed between its separate cells and the former become filled 
with a formative mass, from which new cells may arise according 
to circumstances. 
The following question is closely connected with this develop- 
ment; How is it that this cortical layer is wanting in the Nitelle ? 
I cannot offer any history of the development of the Nitedle which 
will solve this question ; still it appears to me that it may be better 
answered here than from them alone. Moreover the structure 
of the Nitel/e does not differ from that of the germinating plant. 
We have therefore both stages in the Chare: the simple stem of 
Nitella, and one surrounded with a cortical layer, the genus Chara. 
We must be able to draw some conclusion from the observation 
of the successive development of the two. If we expose a plant 
of Chara in a glass of water to the warmth of a stove and light, 
the stems are developed with uncommon rapidity into long thready 
utricles, If they are examined more closely, we observe not only 
that the above double relation of the cells in the cortical layer to 
those in the stem is disturbed, because generally speaking fewer 
must always be seen than would be necessary tocompletely cover the 
central utricle, the stem ; but we find very frequently, in fact nearly 
always, that the cortical cells are completely wanting*. I think 
that we may directly solve the question from this observation. If 
this phenomenon is merely produced by the rapid growth of the 
articulations of the stem, when we apply this to the Witella, we 
have the solution. First, the rapid growth is unfavourable to the 
formation of cytoblasts; secondly, the cytoblastema present is 
rapidlyassimilated by the membranes of the stem; whence, thirdly, 
the very remarkable circumstance happens in the Nit¢ella, that 
there are formed in the internodial cells a very considerable quan- 
tity of starch-cells, in which those cells abound. This has been 
already observed by several persons and may be readily repeated ; 
it is an essential period in the formation of Nitella and of its 
structure in general, such as we find no instance of in Chara, at 
least as far as I know. The cytoblastema which is produced from 
the transformation of starch again becomes converted into starch, 
when the proper time arrives for its again acquiring the state of 
aggregation of starch. This also occurs in the internodial cells 
of the Chare and of the papille of many species ; but whilst in 
* This fact appears also to have been observed by Quekett (see Jahres- 
bericht, &c. von J. Em. Wickstrém, translated by Beilschmied for 1838, 
Breslau, 1843, p. 26) in Chara hispida. The author thinks it follows hence, 
that all Chare are only modifications of one and the same species. 
