22 Veit Bkecher Witteock. 



PL 4, fig. 18 shows a specimen of P. Roettleri (Roth) nob. which 

 has no normal rhizo'id, but which has sent forth, from the mother spore, 

 sg, of the plant, a side branch, which is itself ramified, sending a strong 

 branch downwards and a feebler one upwards. That this side branch 

 has been formed already in the germination of the spore seems to me 

 very probable. The germinated spore would thus in this case have sent 

 forth two processes, one from one of its ends, but the other not from 

 its opposite end, but from one of its sides, and would thus have ger- 

 minated in quite a peculiar manner. 



In the account of the increase of the new plant, originated in the 

 germination of the spore, we will first take into consideration the caul old, 

 and afterwards treat the rhizo'id. In its first stage the cauloid consists, 

 as is mentioned above, of only one cell, viz. one of those originated 

 by the formation of the first transversal cell-wall in the germinated spore 

 cell. This cell now increases apically, and after having attained a certain 

 length it is divided into two daughter cells by a succedaneously formed 

 transversal cell-wall, vertical against the longitudinal axis of the cell. 

 The formation of this wall, as well as of all the transversal cell-walls 

 formed in the bipartition of the vegetative cells, takes place exactly in 

 the same manner as the formation of the transversal wall which appears, 

 in the formation of spores, between the spore itself and the subsporal 

 cell; see above page 18. The lower one of the two daughter cells formed 

 in the bipartition of the first cauloid cell, which is somewhat widened at 

 the base, but as to the rest of the common cylindrical form, no more 

 increases in the same direction, nor is divided, till ramification — or, 

 in fertile specimens, possibly also formation of spores, — takes 

 place. The upper, on the contrary, which is cylindrical with a rounded 

 top, elongates apically in the longitudinal direction of the mother cell 

 till it has become about twice as long as the mother cell, and then in 

 its turn divides into two daughter cells, the lower and shorter of these 

 being purely cylindrical with abrupt ends, but the upper and longer 

 being of the same form as the mother cell. The lower daughter cell 

 now formed has the same nature as the lower of those formed in the 

 first bipartition — that is, it no more increases in a longitudinal direction, 

 nor is divided, except when branches or spores are to be formed — 

 but the upper elongates apically and is divided into two cells, in the 

 same manner as its mother cell. The two cells now formed proceed in 

 the same manner as those formed by the preceding bipartition. Thus 

 there are formed, anew, a lower cell devoid of the power of increasing 



» 



