630 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
The Tetrasporinae comprise the Dictyotaceae only. The very numerous 
genera of Phaeozoosporinae are distributed among the following families : 
— Cutleriaceae, Lithodermataceae, Ralfsiaceae, Sporochnaceae, Arthro- 
cladiaceae, Laminariaceae, Spermatochnaceae, Stilophoraceae, Chordari- 
acete, Elacliistaceae, Desmarestiaceae, Myriotrichiaceae, Dictyosiphonaceae, 
Striariaceae, Encoeliaceae, Sphacelariaceae, Ectocarpaceae, Phaeotham- 
niaceae, Phaeocapsaceae, and Tilopteridaceae. The genera Nodaria and 
Thorea are not placed ; and Adinema is excluded. 
Phaeosporese.* * * § — Prof. T. Johnson makes the following observations 
on various species of Phaeosporeae : — In Carpomitra Cabrerse and Spo- 
rochnus pedunculatus , the mode of growth of the thallus is trichothallic, 
the apices of the branches being occupied by tufts of innumerable hairs 
with basal growth. The sporanges are unilocular and multisporous. 
The receptacle is the modified apex of a branch of the thallus. The 
zoospores of S. pedunculatus are sensitive to light. In Asperococcus 
plantlets arise on the thallus by trichothallic growth, from hairs with 
basal growth, in a mode which shows an affinity with Punctaria rather 
than with the Sporochnaceae. In Arthrocladia villosa the sporanges are 
unilocular and multisporous, and form stalked chain-like sori. Des- 
marestia ligulata has unilocular sporanges containing from 1 to 4 spores, 
and morphologically equivalent to any cell of the thallus. In the mode 
of growth of the thallus, and in the contents of the sporanges, Des- 
marestia shows a close affinity to the Tilopterideae. 
Dictyotaceae. t — From observations made chiefly on Didyopteris 
polypodioides , Prof. T. Johnson regards the Dictyotaceae as forming a 
family of the Phaeophyceae. In the possession of tetrasporanges it does 
not differ essentially from the Tilopterideae, where the non-sexual non- 
motile spores are quadrinucleate. The contents of the antherids have 
hitherto been described as non-motile pollinoids, but the author thinks 
they are probably ciliated antherozoids resembling those of the Cutleri- 
aceae and Fucaceae. In the brown pigment and in the presence of 
isolated scattered oogones in Didyopteris and Spatoglossum , the Dictyo- 
taceae also present characters which belong to the Phaeophyceae rather 
than to the Florideae. The family to which they are probably most 
nearly allied is the Tilopterideae. 
Spirogyra.J — Mr. G. Mann finds that when Spirogyra nitida and 
jugalis grow at a great depth, the filaments present some differences 
from those growing in shallow water. The filaments are from 2 • 5 to 
3 feet long, and are divided into an apical, a shaft, and a foot-portion, 
the cells of which present certain differences. Crystals are of common 
occurrence in the filaments, composed probably of calcium oxalate. 
Ctenocladus.§ — Reviewing his description of this genus, Prof. A. 
Borzi removes it from the ChaBtophoraceae to another section of the Ulo- 
trichiaceae, mainly on account of the structure of the cells, which are 
cylindrical and arranged in filaments branching in one direction only, 
the single chroraatophore being in the form of a parietal plate placed 
* Ann. of Bot., v. (1891) pp. 135-44 (1 pi.). 
t Journ. Linn. Soc. (Bot.), xxvii. (1891) pp. 463-70 (1 pi.). 
t Trans, and Proc. Bot. Soc. Edinb., xviii. (1889-90) pp. 421-31 (8 figs.). 
§ La Nuova Notarisia, 1891, pp. 385-7. Cf. this Journal, 1884, p. 103. 
