292 Bower . — Some Normal and Abnormal 
in a less degree, it may be imagined that the oophytes of 
present Vascular Cryptogams may actually be a much more 
reduced type of sexual generation than some of their an- 
cestors. 
We know from direct observations that abnormal external 
conditions may largely control the vegetative development of 
the oophyte. Two pertinent examples of this may be cited 
in plants not far removed from those under discussion. The 
first is described by Dodel-Port \ who found that when pro- 
thalli of Aspidium violascens are kept submerged, single cells 
at the margin or surface may grow out into confervoid fila- 
ments, some of which, as figured by him, show a marked simi- 
larity to the protonemal filaments of species of Trichomanes . 
The second case is one described by myself 2 . If the fresh 
gemmae of Aulacomnion palustre be grown in water, proto- 
nemal filaments are produced by outgrowth of single super- 
ficial cells, but no leafy buds are formed on the protonema ; 
whereas, on damp soil, leafy buds are produced readily enough. 
Readers will doubtless be able to supply themselves with 
other parallel cases. In presence of such evidence, and in 
treating of organisms which are so insufficiently known as the 
oophytes of the Hymenophyllaceae 3 , it appears to me that 
the greatest caution is to be maintained. We know that the 
Hymenophyllaceae are exceedingly susceptible to changes 
of dampness of the air, and may reasonably conclude that 
such changes may react upon their mode of growth. I 
therefore think that before we can with real security base 
phylogenetic conclusions upon details of external conforma- 
tion of the oophyte in these plants, we require to know more 
of the characters of different species, and of the influence of 
1 Kosmos, 1880, p. 11. 
2 Joum. Linn. Soc. Vol. xx. p. 465. 
3 It is particularly to be noted that the conditions under which those specimens 
were grown, which have been used for the study of the oophytes of the Hymeno- 
phyllaceae, are insufficiently known. Mettenius worked from herbarium material ; 
Rostafinsky worked on material collected in the open ; Goebel’s material was partly 
collected in the open, while the earlier stages were supplied by cultures. My own 
material has been chiefly grown at Kew in an almost uniformly damp atmosphere, 
low temperature, and in shade. 
