M. MUller on the Development of Chara. 323 



XLII. — On the Development of Chara. By C. Muller*. 



[Continued from p. 262. J 



§ 5. The perfect Plant. 



The modifications of the development of the stem in Nitella have 

 been traced with tolerable completeness. In Chara, however, the 

 simple tubes are covered externally with utricular cells which are 

 arranged spirally around them. These are not formed uijtil after 

 the germinating plant has become much elongated and its rami- 

 fications have acquired considerable increase. In a plant which 

 has attained this stage of development several peculiarities are 

 apparent. Such are the evolution of axillary cells to form axillary 

 branches, and the formation of other more or less rounded cells 

 in ascending and descending rows at the articulations of the stem ; 

 lastly, the formation on the stem itself of new papillary cells 

 which are identical with those last mentioned, as in Chara his- 

 pida and crinita, where they sometimes again elongate into arti- 

 culated tubes, and thus give the plants a very rough appearance. 

 The cells themselves do not differ at all in their internal struc- 

 ture from those of the spore-sac. How are these organs formed ? 

 How are the utricular {cortical) cells formed around the central 

 utricle ? Here the process of development of the entire plant is 

 far more complicated than that of the germ. Moreover the his- 

 tory of the development of all the organs, of the branches, shoots, 

 and even of the stem itself, is intimately connected, and we must 

 again commence with the stem. 



To trace the formation of the stem, we must search for that 

 point at which it is developed. This is its apex, the te?'minal bud; 

 which consists externally of a single large cell forming the im- 

 mediate continuation of the stem, and as such, terminating it in 

 the form of a cupola (PI. VI. fig. 11). The bud appears of the 

 same form in the centre of the recently formed whorl of branches 

 whilst still short. Its membrane is extremely delicate and there- 

 fore easily injured. It contains a reddish granular matter (cyto- 

 blastema), which too frequently renders it impossible to arrive 

 clearly at the structure of the bud. If we succeed, however, in any 

 way in removing it — which can only be effected by dissection, for 

 iodine and acids render the contents still more obscure — we find 

 the whole of the interior already covered with cells with exceed- 

 ingly delicate walls (fig. 14). [In this figure the preparation 

 fig. 11 is placed on its vertex, and we are supposed to look in- 

 ternally from above towards the vertex.] This cellular structure 

 consists of a central cell, around which some other cells are de- 



♦ Translated from the Botanische Zeitung for June 26, 1845. 



