i5 
of Marattia Douglasii , Baker. 
Osmunda again shows in the relative time of emergence of 
cotyledon and root, a condition intermediate between the 
Marattiaceae and the higher leptosporangiate forms. The 
peculiar method of emergence of the embryo of the Marat- 
tiaceae was first described by Luerssen 1 . If we admit the 
primitive nature of the Marattiaceae, this peculiarity may 
probably be regarded as an indication that the ancestral 
forms had the archegonium upon the upper side of the 
prothallium, as in Anthoceros, but that with the shifting of 
the archegonium to the lower side, probably to insure fertili- 
zation, the embryo has retained its original position with 
respect to the prothallium, while in the leptosporangiates 
this has been changed. 
There is nothing peculiar in the development of the 
vascular bundles. As usual the first tracheary tissue arises 
at the junction of the bundles of the cotyledon, stem and 
root, and proceeds toward the apices of these organs. Short 
hairs, with the cells rich in tannin, which stain very deeply 
with Bismarck-brown, occur sparingly upon the leaves and 
stem of the young plant. 
One of the most interesting points brought out during this 
investigation was the extraordinary persistence of the pro- 
thallium. Not only does this grow indefinitely when it 
remains unfecundated, but even after the young plant has 
broken through, the prothallium remains fresh and green for 
a long time. The plant shown in Fig. 46 must have been 
nearly a year old, as it was collected in August, 1892, and the 
drawing was made in May 1893, an d not more than two new 
leaves had formed in the meantime : yet the prothallium, 
although torn apart by the growth of the young plant, was 
still green and fresh 2 . 
1 Loc. cit. p. 582. 
2 Since the above was written the writer was fortunate enough to find a number 
of young plants of Botrychium virginianum with the prothallium still attached. 
These were subterranean, but larger than those of B. Lunaria, to judge from 
Hofmeister’s account. Although the sporophyte was in some cases as much as 
ten centimetres high (including the underground portion), the prothallia were still 
fresh, and in some cases, at least, bore fresh antheridia. 
