642 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
three forms is described in detail, with its variations in the two sub- 
genera. 
The antherids arise from specialized cells which terminate the 
generative filaments. Each antheridiophore produces either one or two 
antherids. They are oblong thin-walled sacs, and each contains a single 
oblong hyaline non-motile pollinoid (“ spermatozoid ”). The procarp 
also arises as a special branch from the generative filament. It consists 
of from 3-10 oval cells ; the terminal or carpogenous cell is surmounted 
by the trichogyne, which penetrates through the intermediate layer and 
the cortex to the outside of the sexual shoot. Fertilization takes place 
by contact of the pollinoid with the apex of the trichogyne ; its proto- 
plasm is probably absorbed by the trichogyne, and conveyed to the 
carpogenous cell. After fertilization the carpogenous cell developes, 
by budding, a whorl of cells, the ooblastema-filaments, which soon begin 
to branch, and produce chains of carpospores. Both apogamy and 
apospory were observed in several species. 
The subgenus Sacheria differs from Lemanea proper mainly in the 
antherids being in well-defined patches, rarely confluent ; the procarps 
consist of only from 3 to 4 cells, always developed in and near the 
antherid-zone ; the generative filaments are closely applied to the wall of 
the tube throughout their entire length ; the basids or basal sterile cells 
of the ooblastema-filaments being elongate and cylindrical ; and the 
prostrate form of the protoneme being mainly cellular. 
Bladders of Fucaceae.* — According to Prof. N. Wille, the structure 
of the bladders of the Fucaceae belongs to two different types : — (1) In 
Fucus vesiculosus and Ozothallia nodosa the tissue in which they are 
formed is composed of much-branched filaments ; (2) In Halidrys sili- 
quosus and Cystoseira ericoides the filaments of which it consists are 
parallel, and but slightly branched. The proportion of oxygen in 
bladders which still remained immersed in the water amounts to as 
much as 35-37 per cent. ; they never contain any carbon dioxide. 
Macrocystis and Thalassiophyllum.f — Herr 0. Bosenthal describes 
in detail the vegetative structure of these two genera of Laminariaceae, 
which he regards as constituting a special group, contrasted with a 
second group formed of Laminaria , Alaria , Costaria, and Agarum. The 
distinguishing feature lies in the segmentation of the frond, this again 
depending on a difference in the position of the growing point — in the 
first group lateral on the margin of the lamina, in the second group 
opposite the middle of the base of the leaf, at the point of junction 
between stem and lamina. In Macrocystis the leaves are in consequence 
inserted laterally, and are perennial, while in Laminaria they are ter- 
minal, and are usually thrown off annually ; their duration is not known 
in the other genera of the group. In Macrocystis and Thalassiophyllum 
the growing point divides into two unequal halves, which is not the 
case with Laminaria. In Macrocystis and Laminaria the lamina splits 
up into narrow strips ; while the formation of holes in that of Agarum 
corresponds somewhat to a similar process in Thalassiophyllum. 
* Biolog. Foren. Stockholm Forhandl., i. pp. 63-5. See Bot. Centralbl., xlii. 
(1890) p. 110. 
f Flora, lxxiii. (1890) pp. 105 -47 (2 pis.). 
