Recent Work on the Bryophyta. 267 
that in the classification of this genus far too much stress has been 
laid by systematists upon the presence or absence of hairs and violet 
colouring in the thallus—“ features which are very much controlled 
by the amount of exposure to light and drought which the plant 
experiences.” On the other hand, he emphasizes the comparative 
constancy of the form of the thallus in transverse section. 
Massalongo (24) has published an excellent account of the 
European Ricciaceae, with new and admirable figures of the great 
majority of the species; this memoir forms a welcome supplement 
to the literature of an important and somewhat difficult family, and 
in various respects amplifies the recent treatment of the Ricciaceae 
by Muller in the new edition of Rabenhorst’s “ Kryptogamenflora.” 
Meyer (25) has described in detail the embryology of Corsinia, 
an interesting genus which is in many respects a connecting-link 
between the Ricciaceae and the higher Marchantiales. His 
observations on the development and division of the spores agree 
with those described for Riccia by Beer (Ann. Bot., Vol. 20, 1906) 
and by Lewis (Bot. Gaz., Vol. 41, 1906); the x and 2,r chromosome- 
numbers are apparently 11 and 22. The early development of the 
sporogonium shows an octant-stage, as in the majority of Mar¬ 
chantiales, and the separation of the one-layered capsule-wall from 
the central tissue (archesporium) occurs at a very early stage, while 
the differentiation of the fertile cells (spore-mother-cells) from the 
sterile cells (“ rudimentary elaters”) of the archesporium is relatively 
late. The sterile cells for a considerable time form a connected 
network with spaces in which lie the developing spores, but later 
these cells separate and, after having been depleted of the greater 
part of their contents to nourish the spore-mother-cells, again 
become filled with starch-grains. This paper adds Corsinia to the 
small list of Bryophytes whose life-history is now known with 
tolerable completeness. 
The same author (26) describes a number of abnormalities 
observed in the sexual organs of Corsinia , and discusses these, with 
other more or less similar cases recorded in recent years in various 
Bryophytes, in reference to their bearing upon the phylogeny of 
the archegonium. He lays stress upon these abnormalities as 
furnishing support for the views of Davis, Goebel, Schenck, Hallier, 
Potonie, and others, regarding the origin of the archegonium from 
an organ like the “ plurilocular sporangium ” of the Brown Algae. 1 
Deutsch (5) has cleared up some doubtful points in the 
structure of Targionia hypophylla, and contributed some interesting 
remarks on the classification of the Marchantiales. He finds that 
the thallus grows by a single apical cell, and that the involucre 
around the archegonial group is complete and well-developed before 
the archegonia are fertilised. The present writer has preparations 
which confirm Deutsch’s observations on these two points, but 
cannot agree with Deutsch as to the absence of a rudimentary 
“ elaterophore ’’(represented, it is true, only by a few short spirally 
thickened cells attached distally to the inner surface of the capsule) 
or as to the absence of lobing in the spore-mother-cells. Deutsch 
sets forth an ingenious method for estimating the systematic values 
of various characters of gametophyte and sporophyte in the classi- 
1 See Review of Schenck’spaper, in New Phytologist, Vol. VIII, 
1909, p. 234. 
