388 BOTANICAL GAZETTE [MAY 
Culture method 
In connection with the study of the wild gametophytes, spores 
were planted in flats in the greenhouse and studies of young game- 
tophytes and their development are under way. For a number of 
years gametophytes of E. arvense have been grown with considerable 
success. Each year sporophytes have lived until the primary shoot 
was a couple of inches tall, and in some cases the secondary shoot 
has developed. Because of this the same culture method was tried 
with E. laevigatum. The method used was as follows. An ordinary 
greenhouse flat was filled with sifted soil, a mixture of loam and 
sand being used. The soil was then smoothed and pressed down 
until a firm hard surface was formed an inch or more below the 
top of the flat. This was then flooded with water and allowed to 
stand until the water sank into the soil. Just as the water sank 
to the top of the soil the spores were shaken from the cones on to 
the soil. This was done by tapping the cone hard enough to shake 
the spores from the sporangia. The flat was then covered with a 
piece of glass and set in a sunny room of the greenhouse. Usually 
no more water was needed until the gametophytes were 1 mm. Or 
more in diameter. If, however, the flats became too dry, they 
were watered by holding them in a tank of water until the soil 
became wet from below. After the gametophytes were 1 mm. in 
diameter they were sprinkled with an ordinary garden sprinkler. 
No attempt was made to sterilize st soil, nor were any special 
methods of watering used. 
Flats of E. laevigatum planted in this manner in the middle of 
June grew well and developed archegonia and antheridia until the 
first of September. During the writer’s absence of two weeks the 
greenhouse attendants changed and the flats were permitted to 
dry up. All were killed except one flat, in which sifted cinders 
from a railroad track were used instead of the usual soil. This 
flat survived the drought, and during the middle of September was 
full of sporophytes. Slugs ate these off as fast as they grew, 
however, so that none reached a height of more than a few milli- 
meters. The gametophytes continued to grow, however, and new 
sporophytes developed only to meet the same fate. As winter 
approached the growth became slower and new sex organs did not 
