90 HOFMEISTER, ON 



touch it. The longitudinal growth of the lateral shoots 

 soon surpasses that of the middle shoot, and shortly after- 

 wards the growth of the former in breadth and thickness 

 also exceeds that of the latter. The result is that the 

 median shoot, closely surrounded above and below by the 

 more rapidly growing lateral ones, is pushed to the bottom 

 of one of the narrow crevices formed by the lateral shoots, 

 which shoots are more vigorous in their longitudinal growth. 

 By the multiplication of its cells in the longitudinal 

 direction the median shoot is blended with the two lateral 

 ones, which surround it almost entirely, and far exceed it 

 in size. The shoot formed by the junction of three masses 

 of cells in a state of active longitudinal growth amal- 

 gamates at its sides with the advanced portions of the fore 

 edge of the germ-plant by which it is enclosed. On the 

 one side it amalgamates with one of the wing-shaped 

 lateral portions, on the other with the one half of the 

 median shoot, which in the mean time expanding more and 

 more in breadth, has assumed an entirely emarginate 

 shape. By further longitudinal growth the shoots of the 

 second order make their appearance out of the two narrow 

 crevices which the fore edge of the germ-plant exhibits, and 

 which answer to the limits of the median lobe of the fore 

 edge and its lateral portions. The apex of the young Riccia is 

 furcate. The apical point of the bifurcation is the middle 

 of the fore edge of the median shoot. Each point of the 

 fork exhibits in the middle of its fore edge a deep, narrow 

 incision, formed by the two lateral component parts of the 

 shoot of the second order, which almost touch one another. 

 At the base of this incision is the median shoot, of which 

 the apex alone is free, and not united in growth with the 

 lateral ones, and at the sides of which new shoots, being 

 the median ones of the third order, are in process of 

 formation. An active multiplication and expansion of the 

 cells of the median portion of the shoots of the second 

 order now commences ; this median portion, by its longi- 

 tudinal growth and the continually increasing width of its 

 fore edge, pushes asunder the lateral portions of the same 

 shoot which have hitherto confined it in a narrow crevice. 

 New shoots originate in like maimer out of its angles. 

 The subsequent ramification of Riccia follows the same 



