no Brebner . — On the Prothallns and Embryo of 
Marattiaceae, in being more than one cell thick except at the 
margin, in having the archegonia distributed on a median 
cushion and the antheridia almost anywhere on the lower 
or upper surface. In general appearance the prothallus is 
somewhat different from that of Angiopteris and M arattia 
(cf. Figs, i and 2 with the prothalli figured by Jonkman 1 , 
Farmer 2 , and Campbell 3 ). 
The prothallus may, or may not, be deeply notched at 
the anterior growing margin (cf. Figs. I, 2, and 3), and has 
evidently great capacity for long-continued growth, as in 
the other genera (cf. Figs. 3, 4, and 5). In some cases the 
prothalli attached to the young plants were nearly twice 
the diameter of those bearing embryos. As already indicated, 
the archegonia usually occur on a median cushion, the limits 
of which are not sharply defined. In one instance a small 
cushion, with a few archegonia, was found on one of the 
heart-shaped lobes quite remote from the median line and 
apical margin. This agrees with Prof. Campbell’s statement, 
that 4 , in the Marattiaceae, ‘the sexual organs of the lobes 
are mainly (the italics are mine) antheridia.’ 
The antheridia are truly ubiquitous, occurring freely on 
the under and upper surfaces of the main part of the pro- 
thallus, on the lobes, and also, but more sparingly, on the 
median cushion amongst the archegonia. Marginal cushions 
are not uncommon ; they are literally studded with antheridia 
in such a manner that some of the antheridia open on the 
edge of the prothallus. The occurrence of antheridia on the 
lateral portions of the prothallus agrees with Luerssen’s 
observations on Angiopteris r ° , which Jonkman was not able 
1 Jonkmann, H. F., La generation sexuee des Marattiacees. Archives Neer- 
landaises, T. xv. p. 199. 
2 Farmer, J. B., On the Embry ogeny of Angiopteris evecta , Hoffm. Annals of 
Botany, Vol. vi. No. XXIII. October, 1892. 
3 Campbell, D. H., (a) Observations on the development of Marattia Douglasii, 
Baker. Annals of Botany, Vol. viii. No. XXIX, March, 1894; (b) The Structure 
and Development of the Mosses and Ferns. Macmillan and Co., 1895, p. 254 et seq. 
4 Loc. cit. (b), p. 258. 
5 Luerssen, Ueber die Entwickelungsgescbichte des Marattiaceenvorkeims. Bot. 
Zeit. 1775; Medicinisch-pharmaceutische Botanik, Bd. I. p. 581. 
