i a lg 7 ee 
BRIEFER- ARTICLES 
ANTHOCEROS AND ITS NOSTOC COLONIES. 
THE association of the liverwort Anthoceros with the blue-green alga, 
Nostoc, has long been known and has been studied with considerable 
care. The significance and value of this association have been speculated 
upon; but, as far as I know, no experiments on the subject have been 
reported. The anatomical relations of the two associates have been 
studied and described, but I do not know that cultures of Anthoceros 
from the spore on sterilized soil have been attempted. I shall here describe 
both the culture of Anthoceros, and, at the risk of some repetition of facts 
already recorded by others, the anatomical relations of the Nostoc to the 
surrounding tissue. 
Anthoceros fusijormis Aust., and A. Pearsoni M. A. Howe fruit here 
abundantly in May. Their spores can then be collected almost or quite 
unmixed and free from the spores of other small plants, and may be kept 
air-dry for months. The dry season ordinarily lasts from mid-May to 
October, and during this time usually no rain falls. ‘The spores germinate 
out of doors soon after the first abundant rain has thoroughy moistened the 
soil to a depth of several inches. The natural “‘resting-period” for the 
spores is, therefore, four or five months long, but the spores retain their 
vitality much longer. They may also be made to germinate in much 
shorter time. The ‘“‘resting-period” seems to be, therefore, a matter of 
natural conditions rather than of transmitted habit. 
The soil on which I grew plants from the spore was brought into the 
laboratory from the bank on which these plants, along with other small 
archegoniates, grow abundantly during each rainy season. After thor- 
ough air-drying, the soil was freed from pebbles, pulverized in a mortar, 
and put to a depth of a centimeter or slightly more in crystallizing dishes 
of thin white glass. These dishes were about 8°™ in diameter, 3.5°™ in 
depth, and were covered by the lids or bottoms of Petri dishes. These 
covers do not fit tightly; at the same time that they exclude dust and 
maintain the moisture of the air, they permit fair ventilation. The soil 
Was invariably moistened from the beginning with boiled distilled water, for 
Wished to avoid any accumulations of salts in these undrained cultures 
from using our hard tap-water. These covered dishes were now divided 
55] [Botanical Gazette, vol. 24 
