184 



this species sheds its spores in this general area in April, the last 

 strobili discharging their contents in early May. 



On June 18, 1941, Mr. Wallace Carr and the writer were study- 

 ing the succession along the margins of this pit and were searching 

 for indications of floating and submerged plants, without very much 

 success. For the most part the recently exposed clay and silt were 

 completely devoid of plant life. Since the removal of the water, the 

 substratum is subject to alternate wetting and drying, and although 

 the rain washes down over the sides and runs along the bottom of 

 the pit, the base is not level, so that it collects in the deepest parts. 

 The slopes are fairly steep, but the width of the pit is so great that 

 there is little shading of the bottom, except in early morning and 

 late afternoon. Consequently the fane soil at the base becomes alter- 

 nately inundated in wet weather and more or less baked, though 

 never completely so, in dry periods, cracking into characteristic 

 "cakes." It was on this substratum that hundreds of gametophytes 

 were found several hundred yards distant from mature sporophytes. 

 Although the soil was distinctly cracked, it was not powdery and 

 dusty, but firm enough to permit the removal of "chunks." 



The gametophytes there on June 18 were very numerous and of 

 varying sizes, some hardly visible, some about the size of a pin head, 

 many somewhat larger, varying in diameter up to about six milli- 

 meters. They looked like hundreds of miniature green pincushions, 

 many of them having young sporophytes that were just beginning to 

 project visibly up into the air. Mostly they were a rather soft green 

 in color, some were dark brownish green, while one, noticed several 

 weeks later, was distinctly brownish red. The photographs in figures 

 1-4 were taken on July 8. The largest gametophyte, collected on 

 July 19, was nearly circular in outline and measured 8 millimeters 

 across. It bore no sporophytes, and like some of the other larger 

 ones, had begun to break down slightly near the center. Even at 

 that date, however, there were numerous gametophytes, without 

 sporophytes, that were bright green and vigorous, though a larger 

 number were disintegrating. 



Some of the soil with the gametophytes was brought into the 

 laboratory, where the prothallia were kept alive. They were more 

 or less circular in outline, and somewhat raised in the center. One 

 of the larger ones, about 6 mm. in diameter, is shown in figure 1 ; 



