Ill 



MARCHANTIE/E 



59 



The other Marchantieae are much aHke, and as Targionia 

 was found to be an especially satisfactory form for study, on 

 account of the readiness with which straight sections of the 

 embryo could be made, it was taken as a type of the higher 

 Marchantieae. The first division wall (basal wall) is trans- 

 verse, and divides the embryo into two nearly equal parts. 

 This is followed in both halves by nearly vertical walls 

 (quadrant walls), and these and the basal wall are then 

 bisected by the octant walls, so that as in Riccia the young 

 embryo is formed of eight nearly 

 equal cells. In Targionia, even at this 

 period, the embryo is always somewhat 

 elongated instead of globular. The 

 next division walls vary a good deal 

 in different individuals. Fig. 21, C 

 shows a very regular arrangement of 

 cells, where the first divisions were 

 much the same in all the quadrants. 

 Here all the secondary walls were 

 nearly parallel with the basal wall, and 

 intersected the quadrant and octant 

 walls ; but quite as often, especially in 

 the upper half of the erribryo, these 

 secondary walls may intersect the basal 

 wall. In no cases seen was there any 

 indication of a two-sided apical cell 

 such as Hofmeister ^ figures for Targi- 

 onia, and probably his error arose from Fig. lo.—Corsinia marchantioids 



. - ^ . ^ , J , (Radd). Young sporogonium, 



a study of forms where the quadrant optical section, x 300 (Leitgeb). 

 walls were somewhat inclined, in which 



case the intersection of one of the secondary walls with 

 it might cause the apex of the embryo to be occupied by 

 a cell that, in section, would appear like the two-sided 

 apical cell of the Moss embryo. The regular formation of 

 octants was observed by me in Fiuibriaria Californica, 

 and by Kienitz-Gerloff" and others in MarcJiantia, Grinialdia, 

 and Preissia, and probably occurs normally in all Mar- 

 chantiaceae. 



After the first anticlinal walls are formed in the octants, no 

 definite order could be observed in the succeeding cell divisions, 



1 Hofmeister (i), PL XV. Figs. 24, 25. - Kienitz-Gerloff (i, 2). 



