BULLETIN 
TORREY BOTANICAL CLUB, 
Vol. XIII] New York, April, 1886. [No. 4. 
The Development of the Antheridium in Ferns. 
By DouGLas H. CAMPBELL. 
Plate Liv. 
In a paper read before the last meeting of the American 
Association for the Advancement of Science, I called attention to 
the readiness with which the prothallia of ferns may be grown, 
and their value as types in the study of development. In the 
present paper I have endeavored to give a few hints in regard 
to the study of the antheridium, suggested by a somewhat ex- 
tended study of a number of species. 
In selecting species for study, it is best to choose those that 
are dicecious, or else to study the young prothallia of the monce- 
cious species; as in the larger moncecious prothallia, longitu- 
dinal sections are necessary, while in the small male prothallia of 
such dicecious forms as Asplenium filix-femina, for instance, 
they may be studied by placing the whole prothallium upon the 
slide. 
The observations here recorded were made principally upon 
the latter species and the two species of Onoclea, O. Struthiopteris 
and (O. sensibilis, all of which are almost absolutely dicecious, 
and do not differ in any essential particulars in the formation of 
the antheridium. 
The best results are obtained by growing the prothallia artifi- 
cially, as it is very rare to find them growing naturally, and it is 
avery simple matter to grow them. The spores germinate in 
from three days to a week from the time they are sown, and are 
ready for study in about six weeks time, when under favorable 
circumstances’ abundance of ripe antheridia may be observed. 
The best results were obtained by sowing the spores in fine 
earth and keeping moist, and somewhat shaded, a bell-jar being 
used to prevent too rapid evaporation. Care must be taken. 
