Britton and Taylor : Life History of Schizaea pusilla 5 



A sporangium (Fig. 27) filled with spores was sown at the same 

 time with the free spores on September 5th, and a great number 

 of the spores germinated inside the sporangium sending out fila- 

 ments through a basal break ; when the spores were removed from 

 the sporangium they were found to be more advanced than those 

 germinating outside, the rate of growth of the spores in the sporan- 

 gium in a given time being almost twice that of the other spores. 



Branches were given off from the basal cells of the filaments, 

 sometimes from apical portions of young filaments, and in a few 

 cases the spore cell was found to divide into three primary cells 



(Fig- 17)- 



Intermediate stages between the earliest developed filament 



from the spore and the much-branched protonema are lacking. 



Protoxema 



The protonema occurs on the substratum, or on rootstocks of 

 other plants, as small tufts of a dark green color, growing to a 

 height of 2 mm. and a breadth of 4 mm. 



The protonemal filaments are larger than the protonema of 

 mosses. A comparison was made with Pogonatutn breidcatile and 

 MniiDi! punctatiiiii with the following results : 



Length Breadth 



Cells of Pogonatum brevicaule \ l,c, ^ 



15 // 15// 



96 a 23 // 



Cells of MniiDH punctatuni \ ' 



CqWs oi Schizaea pusilla < 173 n 92// 



(134 yf 38/^ 



It is also seen from the above that the cells of the filaments of 

 Schizaea pusilla are fairly uniform in dimensions. They are 

 densely filled with chlorophyl ; starch is present. The cells are 

 cylindrical, sometimes flattened near the base, in the region of the 

 archegonia. Some few of the cross-walls were found to be per- 

 forated. 



The protonema is copiously branched, the branches being 

 generally single from each of the cells of the filament, generally 

 near the upper end of the cell (Figs. y2, 73). Occasionally three 

 or four in succession will give rise to two branches from opposite 



