SOME PECULIAR FERN PROTHALLIA 
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 137 
LULA PACE 
(WITH ELEVEN FIGURES) 
In September 1906 Miss S. M. HAGuE sent me some fern pro- 
thallia from a swamp in northern Indiana, where they were growing 
luxuriantly on rotten wood. Pieces -of the wood were put into a 
glass jar, which was covered and placed on a table about seven feet 
from a window with a southeast exposure. They were kept very 
moist, yet watered with care, so as not to allow any water to get on 
the plants and thus cause fertilization. In spite of this precaution, 
however, enough moisture probably collected on the plants to permit 
fertilization occasionally, for sporophytes developed at intervals. 
Some of these, as well as many of the gametophytes, were used in 
class work. A few of the sporophytes are about 7 cm. high. They 
resemble St tosson’s figures of Dryopteris spinulosa intermedia 
(Aspidium intermedium Muhl.). Certain peculiarities found in this 
material seem worth describing. Some of the gametophytes are 
still growing and will be watched for further developments. 
Gametophytes 
The prothallia were of the typical heart-shaped form, the larger 
ones being about 5 mm. long. Those on which sporophytes have not 
developed have continued to grow, and many spores, which had been 
lying for a long time in the rotton wood, have germinated. The old 
prothallia have grown to unusual size and taken queer shapes, many 
of them being 15 mm. long, a few 23 mm., and one even measuring 
37mm. The most striking thing about them, however, is the peculiar 
forms developed. A hasty observation of one of these often gives 
the impression of a number of prothallia near together and over- 
lapping, for they often branch, apparently from any part of the plant, 
as in fig. 1, which is a diagram of one of the simpler cases. At one 
point near the margin of another plant 21 of these branches were 
counted, all 1-1.5 mm. long, and each bearing 6-10 antheridia. In 
49] [Botanical Gazette, vol. 50 
