ON THE GERMINATION OF CHAR A. 305 



odd numbers will be on one side and the even ones on the other. The 

 cells 1 and 2 are bounded by walls which form an angle of 45° to 90° 

 with the halving- wall in the centre of the node ; the next, by ex- 

 centric walls, with an inward convexity, which do not reach 

 the halving- wall, and it is only the two last partitions that reach 

 the latter, thus forming the two inner cells at the same time. The 

 first two cells are from the beginning larger than the others, and the 

 succeeding ones are smaller in proportion to their higher number. 

 This relation is not only preserved during future growth, but becomes 

 even more apparent ; and the first cell more especially maintains 

 its advance of the others. It soon completely assumes the upward- 

 arched front surface, and is the first or initial (z) cell, whose free 

 arched portion is the vegetative point of the first stem of the Chara 

 plant. The other cells of the circumference may develop as whorled 

 leaves, chiefly rudimentary, and decreasing in size as they recede 

 from the foreside. With regard to the next change in the initial 

 stem-cell (figs. 25, 26), this consists of an inclined tangential wall 

 dividing it into two cells, an inner one entirely within the node, and 

 an outer one, almost the whole of which projects out beyond the node 

 and has an arched crown. The outer one then begins to grow and 

 form segments after the manner of the apical cell of the stem. Its 

 first segment (n) is separated by an oblique wall inclined outwards 

 and downwards. It still lies partly within the node, and forms with 

 the first-named inner cell the basal node of the first stem, which 

 basal node exactly resembles those on the leaves of older stems. The 

 first segment is divided by a vertical radial longitudinal wall into two 

 parts, of which the free front surface grows out into small leaves, 

 comparable to the stipules of the stem whorls. See figs. 14 and 26, 

 and Pringsheim, 1. c, t- xii., figs. 5 — 7. The succeeding segments of 

 the now free erect apical cell {v) behave in the same manner as those 

 of the grown stem. It is almost superfluous to observe that slight 

 deviations occur in the number and position of the walls from the 

 plan just described. In the explanations of the figures 15 and 16 

 instances of this are noted. There is also sometimes irregularity in 

 the succession of the cells of the circumference, and frequently the 

 ring is open at the back (rarely at the sides) in consequence of the 

 separation of one or two of the cells which usually form it not taking 

 place. 



If we take into consideration the development of the nodes and 

 leaf whorls of the fully-formed stem,* it is quite evident that the 

 above described plan of division in the stem-node of the pro-embryo 

 is simpler than would appear from Pringsheim' s representation, 

 because it approaches so closely to that in the nodes of a fully-formed 

 shoot. Moreover, it may be worth mentioning, that our results were 

 not sought from any theoretical doubts as to the accuracy of Pring- 

 sheim's statements, but founded on direct investigation of cross 

 sections of the nodes, because what we saw in turning the young 

 pro-embryo about to examine the successive profiles of its long axis 

 did not agree with his representations. It is not difficult to obtain 



* A. Braun, " Richtungsverhaltnisse der Saftstromungea, etc. (Berliner 

 Acad. Monatsber. 17 May, 1852.) 



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