M. Miiller 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 Nitellse ? 

 I cannot offer any history of the development of the Nitella 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 Nitellce does not differ from that of the germinating plant. 

 We have therefore both stages in the Charae : 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 to completely cover the 

 central utricle, the stem ; but we find very frequently, in fact nearly 

 always, that the cortical cells are completely wanting*. 1 think 

 that we may directly solve the question from this observation. If 

 this phsenomenon is merely produced by the rapid growth of the 

 articulations of the stem, when we apply this to the JNitellce, we 

 have the solution. First, the rapid growth is unfavourable to the 

 formation of cytoblasts ; secondly, the cytoblastema present is 

 rapidly assimilated by the membranes of the stem; whence, thirdly, 

 the very remarkable circumstance happens in the Nitellce, 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 CharcE and of the papillae of many species ; but whilst in 



* This fact appears also to have been observed by Quekett (see Jahres- 

 bericht, &c. von J. Em. Wickstrbm, translated by Beilschmied for 1838, 

 Breslau, 1843, p. 26) in Chara hispida. The author thinks it follows hence, 

 that all Chares are only modifications of one and the same species. 



