Brown: Apogamy in Phegopteris polypodioides 19 



Nagai ('14), describes cases of apogamy on prothallia of 

 Asplenium Nidus grown on agar-agar and on filter paper saturat- 

 ed with nutrient solutions. These cultures were kept somewhat 

 dry, in bright light, and at room temperature. The occurrence 

 of apogamous sporophytes is also described on prothallia which, 

 after growing on nitrogen- and phosphorus-free nutrient solu- 

 tion, had been transferred to sand saturated with nitrogen-free 

 nutrient solution and left in bright light and at higher tem- 

 perature. He does not attribute the development of these 

 apogamous outgrowths to dryness but to unfavorable or un- 

 known internal physiological conditions. 



Stokey ( '18) reports a case of apogamy in the genus Dicksonia 

 and a few cases in the genus Cyathea. These occurred in cultures 

 which had been exposed to rather intense light and grown on a 

 medium of moist peat. While she does not consider dryness to 

 be the determining factor, and while she does not state definitely 

 that the intense light was the stimulus, she is of the opinion 

 that the determining factor in one case of apogamy is not 

 necessarily the determining one in another. 



Steil ('i8) found apogamy occurring in the genera Pellaea, 

 Pteris, and Aspidium, in cultures on nutrient solution, sphagnum, 

 nutrient agar, peat, clay, and loam, which were kept under bell 

 jars in a Wardian case in the greenhouse. He does not consider 

 the cultural conditions as the factor which induces apogamy in 

 any of these cases. 



Material 



While collecting fern spores in and about Ithaca, New York, 

 during the summer of 191 5, my attention was called to a sporo- 

 phyte of Phegopteris polypodioides Fee growing on a lawn in the 

 city. It had been transplanted from its native habitat and did not 

 appear normal or healthy, owing, doubtless, to the unfavorable 

 conditions under which it was growing. As there was only one 

 fertile frond, and this a small one, few spores were obtained. 

 Cultures were made from these spores in the early fall upon 

 Prantl's and Knop's full nutrient solutions and on certain 

 modifications of these solutions. After the spores were sown 

 the cultures were placed before an east window where condi- 

 tions of light and temperature were approximately uniform for 

 all. Once each week the prothallia were transferred to fresh 



