1 1 6 Steil. — Apogamy in Nephr odium hirtipes , Hk. 
So far as possible an attempt was made to check the influence of the 
cultural conditions on the development of archegonia and the formation of 
embryos of apogamous origin. When spores were sown on soil in different 
parts of the greenhouse the prothallia of Nephr odium hirtipes always pro- 
duced embryos apogamously. Variations in the illumination, the strength 
of the nutrient solution, or the temperature, resulted neither in the produc- 
tion of archegonia nor in any essential difference in the manner of formation 
of the embryos. A number of species of ferns in which fertilization is 
known to occur were also grown in the Wardian case, but they never pro- 
duced embryos apogamously under these conditions. 
Spores of Asplenium nidus avis and N ephr odium molle obtained 
through the kindness of Dr. George T. Moore, Director of the Missouri 
Botanical Garden, were sown, and the resulting prothallia were also subjected 
to the same cultural conditions under which the prothallia of N ephr odium 
hirtipes were grown. In both species antheridia and archegonia were pro- 
duced in large numbers and embryos appeared only as a result of fertiliza- 
tion. Therefore, my cultural conditions were not such as to induce apogamy 
in Asplenium nidus avis , in which it was observed by Nagai (1914), or in 
N ephr odium molle \ in which induced apogamy was reported by Yama- 
nouchi (1908 c). 
In preparing material for cytological study, various fixing agents were 
used. By far the best preparations were obtained with the Flemming 
fluids. Flemming’s weaker solution gave the best results for the prothallia 
and the young embryos ; the Flemming medium solution proved most 
•satisfactory for work on the sporogenous cells. Sections were cut usually 
five or six microns in thickness. For some of the studies of the sporogenous 
cells, sections were made eight or ten microns in thickness. Although a 
number of stains were used, Flemming’s triple stain (safranin, gentian violet, 
and orange G) gave the best results. 
Observations. 
The Gametophyte of Nephr odium hirtipes. 
The spores of N ephr odium hirtipes usually remain capable of germina- 
tion for about a month after they mature, although some of them retain 
their germinating power for a much longer period. 
The spores germinate within a few days after they are sown. Nothing 
unusual was observed in the germination of the spores or in the early stages 
of development of the prothallia. The prothallia become typically heart- 
shaped (Figs. 1 - 3 , PI. V). Glandular hairs are produced on both surfaces, 
especially on the anterior portion and along the margins of the prothallium. 
Archegonia are never produced, and antheridia are not formed, as a rule, 
under ordinary cultural conditions. Spermatogenesis has not been studied 
