BROWN: APOGAMY IN PHEGOPTERIS POLYPODIOIDES 25 
In the experiments of the second year apogamous outgrowths 
were first observed in the laboratory cultures on Knop’s full 
solution about four to six months after sowing. Subsequently 
they developed in essentially all the cultures. These outgrowths 
were very diversified in form, and while some originated as 
cellular masses, at various places on the archegonial cushion, 
the majority developed as outgrowths of the prothallia in the 
region where the sinus usually occurs. It was only in rare cases 
that sexual organs, either antheridia or archegonia, formed on 
the prothallia bearing apogamous outgrowths. 
Fic. 7 shows an apparently normal and slightly elongated pro- 
thallium with a broad lobed apex. No sexual organs developed, 
although a well-developed archegonial cushion was present. 
From the region of the sinus a lobe formed. Narrow at first, it 
gradually widened and then branched to form two prothallia 
with broad apices, each having a sinus. In the thickened 
central region of each of these branch-prothallia a cluster of 
tracheids appeared. In the meantime, from the center of the 
archegonial cushion of the original prothallium a cellular mass 
‘began to form. This continued to grow as a thick conical mass. 
The apogamous outgrowth shown in Fic. 8 formed as a 
lobe from the sinus of a very irregular, elongated prothallium 
whose apex was lobed. This lobe, which later became an apog- 
amous sporophyte, was at first one cell in thickness and several 
cells in width. It broadened and thickened into a bulbous 
cellular mass, then elongated and formed a series of tracheids 
in the center. Finally it reverted to a filament one cell in thick- 
ness. 
Fic. 9 shows an apogamous outgrowth which originated as 
a lobe from the irregular apex, a little to one side of the center 
of an elongated prothallium. This lobe broadened and thickened, 
forming two branches. One branch did not develop as rapidly 
as the other and appeared more thallus-like, being only one 
cell in thickness. The other branch, after elongating slightly, 
broadened into a prothallium thickened at the center and with 
a heart-shaped apex. Tracheids formed in this thickened area 
and a small branch developed at one side of the prothallium 
near the apex. 
e€ apogamous sporophyte shown in Fic. 10 developed 
first as a cellular mass on the meristem near the sinus of a very 
