The Marchantiaceae of Sinsinawa Mound. 
SISTER M. ELLEN. 
This family is represented by three species: Marchantia poly- 
morpha, Conocephalum conicum, and Preissia commutata, all 
of which grow in abundance and fruit luxuriantly year after 
year in the locality of Sinsinawa Mound, Grant County, Wis- 
consin. The writer has been interested in observing and noting 
the seasons for the discharge of the spermatozoids, reduction 
division, and the subsequent development. of the sporophyte 
and spore dissemination in each of the three species. All three 
plants are found in great profusion on the north side of a rock- 
bound, spring creek, Marchantia polymorpha on the lower 
level, just at the water’s edge, and, in the rainy weather, some- 
times almost submerged; while Concephalum conicum and 
Preissia commutata are often very closely associated in dense : 
mats a little higher up on the rocky bank. Preissia commu- 
tata is also found far away from water, fruiting most luxu- 
uriantly on quite dry rocks. 
The spermatozoids of Marchantia polymorpha are often 
ready for dispersal about May first. However, there is some 
variation in all of the activities of this plant. This is due not 
only to differences in the seasons but also to differences in the 
individual plants. The variations in the time of fertilization 
are easily noted in Marchantia polymorpha by the unevenness 
in the elongation of the stalks of the archegonial heads as these 
stalks begin to lengthen only after fertilization has occurred. 
The formation of the tetrads occurs as early as June fifteenth 
and the spores are ripe about the first of July. It is quite 
possible sometimes to collect plants that are much less mature 
at this time. 
In Conocephalum conicum, the spermatozoids are discharged 
about June fifteenth and there is considerable uniformity in 
1 Sister M. Ellen, Germination of the Spores of Conocephalum coni- 
cum, (Amer. Journ. Bot. 7:458,464. Pls. 34, 35. 1920.) 
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