322 M. Pringsheim on the Pro-Embryos of the Charse. 



pends upon the history of the growth of the shoots of Charce, 

 for the complete representation of which we are indebted to 

 Alex. Braun*. It likewise requires a thorough examination of 

 the formation and structure of the lateral shoots given off from 

 the nodes and leaf-axils of the Charce. 



I suppose the general structure of the Charce to be well known; 

 and with regard to the history of the development of their branches 

 I merely call attention here to the fact that every branch and 

 every bud (or branch-rudiment) of the CharcBy as in the Cormo- 

 phyta generally, terminates in a vegetative cone, from which 

 the formation of the whole of the morphological segments (inter- 

 nodes, nodes, and leaves) issues directly or indirectly; and I 

 may add, further, that the vegetative cone of the Chara is formed, 

 not by a complex cellular body, but of a single cell, which is 

 therefore the vegetative cell. I further refer to the fact that the 

 cortication of the joints of the stem and leaves depends upon the 

 neighbouring nodes, the cortical segments descending from the 

 upper nodes coalescing with those ascending from the lower 

 nodes to form a coherent cortical coat. 



It is well known that in the Chares, as in leafy plants in 

 general, branches issue from the leaf-axils at the nodes, which 

 equally increase the stock and repeat the growth of the parent 

 branch. 



In Chara fragilisj to which species the following statements 

 refer, only a single lateral branch usually issues from the younger 

 nodes : this, as Al. Braun has shown, stands in the axil of the 

 oldest leaf of the whorl. It differs from its parent shoot only 

 in that the complete cortication of its first (lowest) joint takes 

 place entirely from the upper node, its basilar node forming no 

 ascending cortical segment. 



In older nodes of this plant which have survived the winter, 

 we find, on the contrary, a greater number of shoots rising from 

 one whorl of leaves, and now no longer exclusively from the 

 axil of the oldest leaf. 



These later-produced lateral shoots appear at the same time 

 more or less abnormally altered, and a closer examination shows 

 that two kinds of structures, of very different morphological 

 value, occur amongst them. 



Some of them are distinguished from the quite normally 

 barked shoot, produced at a much earlier period in the axil of 

 the oldest leaf, by an entire absence or a deficient development 

 of the bark on their lower parts. This alteration usually affects 

 only the lowest joint and the leaves of the first whorl, but here 

 and there also the following joints and whorls. 



* " Ueber die Richtungsverhaltnisse der Saftstrome in den Zellen der 

 Characeen," Monatsber. der Berliner Akad. der Wiss. 1852 & 1853. 



