260 BOTANICAL GAZETTE [MARCH 
earth in flower pots so thickly as to be visible to the eye. The soil was kept 
from drying by applying distilled water. Cultures of C. glauca showed a 
green growth over the surface of the soil in six or eight weeks. This growth 
was examined after four months and proved to be a practically pure culture. 
There was no evidence at this time of development of thallus layers, the struc- 
ture being gelatinous-granular. The central more moist portion of the culture 
was green, portions nearer the margin of the pot yellow-white, and the margin 
white. Microscopic examination showed that the white margin was composed 
of the lichen hyphae, while other portions of the culture showed the algae 
present. The thallus layers began to form in six to nine months, the young 
thalli arising from granules, each of which often arise from two or more soredia. 
The lichen hyphae were found to become coherent over small areas, and the 
algae in turn became more deeply seated in the mass. These young squamules 
were at first few and widely scattered, but later they were seen in large num- 
bers over the surface of the soi 
TOBLER also made a series of cultures on earthen plates. By keeping the 
air and soil moist in the plate, the hyphae grew luxuriantly. Then he allowed 
the cultures to dry out for two months. On moistening again, soredia-like 
masses appeared at certain points over the surface of the soil. Some of these 
masses were white and composed wholly of lichen hyphae, while others were 
pale or darker green. These masses increased in size slowly, but did not 
differentiate into thallus layers 
anging-drop cultures were also tried. In three months the soredial 
masses had grown considerably, and the lichen hyphae were seen radiating 
beyond the algae in all directions, though the algae had for a time developed 
more rapidly than the hyphae. Some of the soredia disintegrated and gave 
rise to many free spherical algae, which he thinks may have passed through a 
motile condition. Lichen hyphae were seen growing over these algae, but only 
occasionally attached to them. 
e responses to conditions of moisture and light were studied. It was 
found that soredia from both species would grow luxuriantly after the branches 
bearing them had been kept in a dry room at about 10° C. for five months. 
Both the lichen and the algae retained their vitality and grew when moisture 
was again applied, but the former better than the latter. After cultures had 
remained in the dark for two or three months, no remains of the algae could 
be found, while the lichen hyphae had grown well, probably becoming sapro- 
phytic on the algae. 
TOBLER’s results correspond well with what has been observed in nature, 
where soredia-like growths are often observed growing about patches of 
Cladonia. e his cultures, these show in some places a pure white color due 
to strong development of lichen hyphae, and in other places a light or darker 
green color, depending upon the number of algae present. The soredia grow 
slowly both in nature and in cultures. A considerable amount of moisture is 
necessary for the development of the soredium as a whole, yet the soredium 
