170 BOTANICAL GAZETTE [MARCH 
opment given by Kny. He (14) reported that the first wall in the 
antheridium is always flat instead of funnel-shaped, as in the polypods, 
and that the discharge of sperms takes place through a star-shaped 
break in the cover cell. 
When BavKE (3, 4) continued his investigation of different pro- 
thallia, he added Lygodium japonicum to those of the Schizaeaceae 
already examined. Here he pointed out the long-continued persist- 
ence of the apical cell. He also found on well-developed prothallia 
archegonia alone at first and antheridia only when the prothallia 
were considerably older. The exit of sperms here, he reported, is 
provided for by the throwing off of the cover cell. 
Her (12), working with the same species of Lygodium, confirmed 
both of these points. He studied also Aneimia Dregeana, A. Phylli- 
lidis, A. fraxinjolia, and Mohria Caffrorum, and gives as an additional 
distinguishing mark of the whole genus warty (knotige) thickenings 
of the side walls of the prothallial cells. 
Methods 
The soil in which the prothallia used in the present investigation 
were grown was a mixture of loam and sand. Six-inch pots were 
filled to within two inches of the top with coarse stones loosely mixed 
with Sphagnum to facilitate watering and to prevent the dirt from 
sifting through. One-half an inch of well-packed soil covered this, 
and over the top a thin layer of soil was sifted through a fine sieve. 
After sterilization this fineness of the upper soil facilitated the removal 
of prothallia for study. Pots and soil were sterilized in steam for 
several hours and, after the sowing of the spores, were kept covered 
with glass and watered from below. The prothallia were grown in 
a greenhouse where the temperature was always near 100° F. and 
lighted with diffuse light from above. 
The early stages were obtained free from dirt by sowing the spores 
on porous clay plates and keeping these in Petri dishes with a little 
distilled water. Spores were also germinated on the surface of dis- 
tilled water and of 0.6 per cent. Knopf’s solution. Before drawings 
were made the prothallia were always carefully compared with the 
same stages on dirt, to determine whether the form or course of cell 
division had not been altered by the change of medium. 
