CULTIVATION. 
397 
are formed on its under surface, of two kinds, one 
called Antheridia, and tlie other Archegonia ; the first 
(of which there are generally between 30 and 40) con- 
taining round cells, called sperm cells, which contain 
vermicular spermatozoids that issue from the cells 
when arrived at maturity. The cells of the Archegonia 
differ considerably in their structure from the Anthe- 
ridia; they contain an embryonal sac, which at a certain 
period protrudes from the cell, and with which the 
moving spermatozoids are said to come in contact, and 
thus produce fertilization ; soon after this the embryo 
sac is changed, a bud is formed, and ultimately a young 
Fern Plant is gradually developed, and in time the 
Prothallium decays. This singular phenomenon excited 
considerable interest, and has been carefully inves- 
tigated by the late Professor Henfrey and other 
eminent microscopists.* 
Although the above is only an outline of the prin- 
cipal points of this curious subject, yet it will be suffi- 
cient to draw the attention of Fern seed sowers to the 
subject, and materially assist them in understand- 
ing, and arriving at the cause of the many anomalies 
in the good and ill success attending the raising of 
Ferns from seed. Much has, however, yet to be 
investigated before any rule can be arrived at ; such as 
why the Desmobry a division does, as a general rule, pro- 
duce plants from seed in the greatest abundance, even 
to some species becoming the weeds of the hothouse; 
while, on the other hand, those of the division Eremo- 
brya are comparatively few, and may be considered 
the exception and barrenness of this rule. The differ- 
* Henfrey, in Linncean Transactions, vol. xxi. 1853. 
