ON REPRODUCTION, 878 
Archegonia differ considerably in their structure from the 
Antheridia, they consist of bottle-shaped cells into which 
the spermatozoids have been seen to enter, and are 
supposed to fertilize the embryo contained in the cells, the 
result being the production of a young plant on the upper 
surface of the prothallium, as above stated. According to 
what is now explained a prothallium is monoecious, in some 
cases supposed to be dicecious. The latter having recently 
been found to be specially the case with the prothallia 
of Osmwndew. This singular discovery has excited con- 
siderable interest among physiologists; and has been care- 
fully investigated by several, especially in this country, by 
the late Professor Henfrey, as recorded in “ Linnean 
Transactions," vol. xxi, 1853. Recently considerable 
attention has been paid to the subject by M. E. Meyer, 
Inspector of Carlsruhe Botanic Gardens, who in the 
" Gartenflora" for February, 1875, gives his practical 
experience regarding raising Ferns from spores. He says 
he has only succeeded in raising one plant of the genus 
Gleichenia, G. dicarpa, and one plant of Marattia, M. lati- 
folia,* and that he has failed in raising Hymenophhyllez, E 
Which he accounts for by the moist nature of the fronds, 
and the spores bursting in the sporangia soon losing ` 
their vitality by becoming dry. 
Much investigation is, however, required before many 
circumstances attending the germination of spores can be 
explained, such as, why the Desmobrya division does, as a 
general rule, increase the abundance of spores, even to ` 
. Some species becoming weeds in the hothouses; while, on 
. the other hand, those of the division Eremobrya are com- 
paratively few. 
: jx This, however, is no rule, for about 20 years ago numerous plants — 
of Marattia cicutefolia were raised from spores at Kew, Ee 
