Igrt] BRIEFER ARTICLES 401 
smaller than the neighboring ones which are not concerned in embryo 
formation. Embryos are formed on the inner sides of the lobes, as well 
as a-short distance back of the apical notch. Long ribbon-shaped 
prothallia without apical notches also develop sporophytes at their 
distal ends. Sporophytes are often formed, therefore, in regions quite 
distinct from the meristematic area in which archegonia are ordinarily 
developed. 
Soon after the beginning of embryo development, hairs appear 
surrounding the region of active growth. These originate from the 
area of the prothallium which is involved in the development of the 
embryo. Still later, the embryo projects from the prothallium, some- 
what inclosed by the hairs, each of which is composed of several cells 
with large nuclei. As the embryo continues to grow, the primary leaf, 
from the petiole of which numerous hairs develop, makes its appear- 
ance. Later the primary root and stem are formed. At no time was 
there any evidence of the development of a structure which could be 
thought to correspond to a foot. In several cases two sporophytes 
began their development on the same prothallium. From studies so 
far made, it appears that both interior and surface cells of the pro- 
thallium are involved in the formation of the sporophyte. 
During the present season, apogamous embryos have begun their 
development upon a large number of prothallia of this species in four 
cultures growing upon peaty soil. The first embryos were observed 
about one month after the sowing of the spores. : 
So far as I know, apogamy has not been previously reported in 
Pellaea atropurpurea, although Worontn (1907) reported its tnaest 
tence in P. flavens, P. nivens, and P. tenera.—W. N. Stet, University 
of Wisconsin, Madison. 
