THE DEVELOPMENT OF THE PROTHALLIUM OF 
CAMPTOSORUS RHIZOPHYLLUS 
tok ei Ck ET? 
(WITH PLATES XII AND XIII AND EIGHT TEXT FIGURES) 
In this region the spores of Camptosorus rhizophyllus mature 
from June to October. The long axis measures 18-24 u, and the 
shorter 12~20. They contain a few small oil globules, but are 
destitute of chlorophyll. The nucleus is inconspicuous in the living 
spore. The perinium is thick, dark, and shows many sharp, irregu- 
lar ridges with areas of unequal thickness intervening (figs. 47-55)- 
The exospore is seen with difficulty, if at all, as the perinium is 
very rarely pushed off when the spore germinates. 
The spores germinate slowly. The greater part of the writer's 
material was taken from fronds collected October 26, 1912, and 
kept between sheets of filter paper in a book in the laboratory. 
On November 22 the sporangia, after being scraped from the 
fronds, and crushed lightly to free the spores, were sown on well 
sterilized soil in clay saucers. The saucers of soil were protected 
from currents of air by bell-jars supported on small blocks of wood 
to allow proper ventilation, and were kept moist in a well lighted 
greenhouse at an average temperature a little above 70 F. The 
first sign of green was noted with a magnifier on December 17- 
On February 4, 1913, abundant antheridia were found on the 
larger prothallia, and one week later a few archegonia were found. 
On March 22 many old antheridia and archegonia could be found 
on the large prothallia. Other spores collected October 26, 1912, 
“were sown December 23, and kept under the same conditions aS 
the above, but out of direct sunlight. In these cultures the first 
sign of green was noted January 30, 1913. Other spores sown 
January 3 and kept in the light, where on days of bright sunshine 
the temperature reached 80° F. at midday, showed the first sign 
of green on January 30. In all these instances the prothallia wer 
composed of 3-10 cells before their color was noted on the soil. 
Spores sown on boiled tap water, and kept under the same conditions 
Botanical Gazette, vol. 57] [228 
