iqiq] STEIL—PTERIS 475 



Prothallia were found, in one instance, growing from both 

 surfaces of the leaf (fig. 5). These closely resembled the prothallia 

 grown from the sp>ore. The largest one of these was ribbon-like, 

 but the others were mere filaments, each consisting of a single row 

 of cells. On the former an antheridium {a) was produced. 

 Rhizoids had been formed from the same prothallium. Two 

 antheridia (a, a') had also been developed by a filament produced 

 from the other side of the leaf. From one of these the antherozoids 

 were discharged when the living prothallia, still attached to the 

 lamina of the leaf, were examined under the microscope. The 

 antherozoids were normal in appearance and actively motile. 

 The prothallial growths were surrounded at their points of origin 

 by normal sporophyte cells. 



The gametophytic portions, present on the lamina of the primary 

 leaf, may be large, as represented by figs. 6 and 7, in each case of 

 which the terminal portion is distinctly prothalloid. In addition 

 to the large gametophytic portions, a number of smaller regions of 

 the same nature were present on the lamina of the sporophyte 

 represented by fig. 7 {c, d, e,f) and a single one by fig. 6, b. These 

 were almost wholly surrounded by sporophytic cells. A highly 

 magnified view of b is represented by fig. 9. There is, as the figure 

 shows, a sharp line of demarcation between the cells of the two 

 generations. The cells of the gametophytic portion slightly project 

 above the surrounding sporophyte cells. The smaller areas (fig. 

 7,e,f) were partially surrounded by cells of a somewhat intermediate 

 character (n). The chloroplasts in these cells were less numerous 

 and smaller than those in the neighboring gametophyte cells (fig. 

 10). Even in the Hving condition this area was almost colorless 

 as compared with the dark green gametophytic areas, and could be 

 readily distinguished with a hand lens. A cell of the same character 

 as those in the paler region just described was found, in one instance, 

 in the larger gametophytic portion represented by fig. 7. This cell 

 was wholly surrounded by ordinary gametophyte cells (fig. i). 

 From the lower part of the petiole, represented by fig. 6, a pro- 

 thallial portion (p) had been formed. A leaflike and sporophytic 

 growth (s) had also been produced in this case. Three projections 



