Notes. 
161 
prothalli produced show any peculiarities. The spores seen already 
possessed a thick wall on which indications of sculpturing were 
apparent, and a single nucleus was present in each. 
When the unnatural conditions under which they developed are 
borne in mind, it is not surprising that many imperfect sporangia 
were found. Such sporangia were in fact the more numerous. Some- 
times the arrest of development had taken place before the tapetum 
had originated from the archesporium ; but more commonly the double 
layer of tapetal cells was present, surrounding a sporogenous cell 
which had become highly refractive, the nucleus being indistinguish- 
able. The annulus could be made out, but its cells were thin-walled 
and colourless, and the whole sporangium was pale and more flattened 
than one of the same age in which sporogenous tissue had formed. 
No evidence has yet been obtained of the production of sporo- 
phytes, showing vegetative organs, upon the cylindrical process; but 
one example was seen in which a group of sporangia, situated on the 
apex of the process, was surrounded by ramenta. 
Scolopendrium vulgare , L., var. ramulosissimum , Woll. 
The cultures of this Fern were made in the manner already 
described for Lasiraea dilatata. The spores were obtained from 
a plant grown in the open air in the Royal Gardens, Kew. 
The prothalli were at first heart-shaped, and on many of them 
normally produced embryos developed. No further changes ensued 
in those on which young plants were present, and they soon became 
colourless and died. In those which had remained unfertilized, 
however, the apex continued directly into a cylindrical process 1 , which 
was of considerable thickness, and in some cases attained a length 
of 5 mm. The lateral portions of the prothallus showed no further 
growth, and became in time brown or colourless appendages to the 
base of the cylindrical process. On the process were numerous 
archegonia, and its prothallial nature was still further shown by the 
presence, in some instances, of thin lobes of tissue, which generally 
bore antheridia. Sections through the process in this stage show 
that the archegonia are normally formed, and reach almost to the 
apex, and that tracheides are absent from the tissue. The archegonia 
1 Prothalli of Scolopendrium , which from the brief description given of them 
appear to have borne similar processes, are mentioned by E. J. Lowe in the 
Gard. Chron., November io, 1895. They were not investigated further. 
M 
