BRIEFER ARTICLES 
APOGAMY IN PELLAEA ATROPURPUREA 
In the course of a study of fertilization and related phenomena 
in several ferns, a culture of Pellaea atropurpurea (L.) Link was found 
to have developed embryo sporophytes apogamously. The spores of 
this species were collected in October and sown on clay soil December 
13, 1910. The soil was sifted into a small pot, moistened with water, 
and sterilized in an oven. The culture was kept under a bell jar in a 
Wardian case in the university greenhouse. Watering was found 
necessary but once, and was accomplished from below with — 
water. t 
The prothallia grew rather rapidly, and hundreds carefully exam- 
ined at various times showed no indications of antheridia or arche- 
gonia. Two and one-half months after the spores were sown, the first 
indications were noticed of the development of apogamous embryos. 
Many prothallia were again examined on both surfaces for the appear- 
ance of sex organs, with negative results. On March 13, 1911, 110 
prothallia were examined with special care; 47 bore sporophytes in 
various stages of development, but no sex organs were found in any 
case. 
At an early stage in development it is difficult to distinguish between 
young antheridia and rhizoids. Young antheridia may be hidden 
among the rhizoids and escape attention; rhizoids, however, were in 
no case produced in great abundance in the culture in question. Thus 
the possibility is not excluded that rudimentary antheridia may have 
been formed; but my observations make it certain that none developed 
beyond the earliest stages, and that no archegonia were produced on 
these prothallia at any time. 
The prothallia of this fern are of a darker green color than the pro- 
thallia of several other species in my cultures. They are generally 
heartshaped with a deeply cut notch, but many irregularly shaped pro- 
thallia occur. The first appearance of the apogamous embryo is indi- 
cated by a small darkened area usually a short distance back of the 
growing point. This, as sections made at this time show, represents 4 
region of active division, the prothallial cells concerned being much 
Botanical Gazette, vol. 52} -— 
