1914} PICKETT—PROTHALLIUM OF CAMPTOSORUS 229 
as the above mentioned cultures, showed the beginning of germina- 
tion in 10-14 days. While spores collected in October germinated 
best before the first of February, a considerable percentage germi- 
nated as late as the last of March, having been kept in the dry air of 
the laboratory in the meantime. Spores collected from the usual 
habitat in March show a higher percentage of germination than 
those collected earlier and kept in the laboratory. Only a few 
mature; unopened sporangia may be found in the field as late as 
March, so but few spores can be secured at that time. 
All the spores sown at one time and under the same conditions 
do not germinate and develop uniformly into prothallia. A small 
bit of soil, bearing prothallia, taken from any one of the cultures 
mentioned above, would show, up to the first of May, widely 
different Stages of prothallial growth. Many times the writer has 
found on the same bit of soil the intermediate stages from prothallia 
composed of two or three cells to mature plants 2-3 mm. wide, 
and bearing antheridia and archegonia. That some of the small 
prothallia were dwarf male plants is beyond doubt, because of the 
Presence of antheridia. But that some of the spores were late in 
germination is clearly indicated by the constant recurrence of 
these gradations in development accompanied by a continual 
mcrease in the number of mature specimens. The plants from 
Which the photographs reproduced in pl. XIII were made were 
taken at one time from the same portion of one culture, and had 
exactly the same conditions for germination and growth. 
Germination of the spore 
When the spores are placed under the proper conditions for 
germination, they absorb water and increase in diameter from one- 
fourth toone-half. The swelling is followed bya rupture of the perin- 
tum and the exposure of the spore contents. The writer has been 
unable as yet to determine whether or not there are two distinct 
walls within the perinium. If present, they are quite transparent. 
ugh the opening in the perinium may be seen the oil globules, 
Sometimes an inconspicuous nucleus, and after a few hours a few 
Small chloroplasts. From this point two lines of development have 
been noted, 
