464 Miss L. Digby. [Apr. 15, 
apogamy, with the exception of true parthenogenesis, have been encountered. 
Our thanks are especially due to Mr, C. T. Druery, who has kindly supplied 
us with the original fronds, and to the Curator of the Chelsea Physic Garden, 
who has most carefully cultivated the plants with excellent results. 
The aposporal character of Nephrodiwm pseudo-mas var. cristata apospora 
appears to have been first noted by Dr. F. W. Stansfield. It occurred as a 
sport in a very damp fernery. Our fronds were pegged down in pans of moist 
earth, and the cultures have been grown in a greenhouse kept at an average 
temperature of 55° to 60° Fahr. in the winter and of 65° to 70° Fahr. in the 
summer. It was found that no aposporous growths appear until the fronds 
have been pegged down, and in each case the fronds were severed from the 
plant, as this was found to greatly encourage the production of the growths. 
The aposporous growth is rapid and prolific; fronds treated during the 
spring and summer showed prothalli, bearing embryos, in three weeks’ 
time. By the autumn these young plants were sufficiently matured to have 
their leaves layered, and these shortly exhibited the same characteristic 
feature. It is immaterial as to which surface of the frond is in contact with 
the soil. So far as has been ascertained this fern remains very constant in 
character, and continues to breed true. In the plants grown at Chelsea, no 
trace of a sporangium or sorus has appeared on any of the leaves. 
The prothallial growth originates either from the surface, or more frequently 
from the edge (fig. 1) of the frond. It is at first discernible as a small out- 

Fic. 1.—Prothallial growth from apices of pinnule. p.g., prothallial growth. 
pin., pinnule. 
