84 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Phaeozoosporeae having only asexual reproduction. The investigation 
also furnishes material for further consideration of the much-debated 
question of the relations of Chorda to the other Laminariaceae.” A. G. 
Resistance of Marine Algae to Cold. — H. Kylin {Bor. Deutsch . 
Bot . Gesell. , 1917, 35 , 370-84; see also Bot. Centralbl ., 1919 , 140 , 
135). An account of experiments on various marine alga? in certain 
degrees of cold water, maintained at a constant temperature. The algae 
vary greatly. Trailliella intricata was killed after three hours’ exposure 
to -2 - 9°C. ; while Fucus vesiculosus, Nemalion mullifidum and others 
remained unharmed by ten hours in a temperature of - 18° to - 20° C. 
Between these extremes stand species of Laminaria. The young plants 
of L. saccharina are more sensitive than older plants. The author 
draws conclusions concerning algal distribution in Swedish waters. The 
determining factor is the sinking of the surface of the water in the 
winter, whereby the algae are laid bare and exposed to the winter cold,. 
The Laminaria species are only covered by 0 • 60-0 ‘65 m. ; and the 
same applies to the sensitive Laurencia pinnatifida. On the other hand, 
the cold -resistant Facus vesiculosus and Ascophyllum nodosum can exist 
immediately below mid-tide mark at a depth of 0'5m. The resistance 
of sensitive species was not raised by treatment with sugar solution and 
concentrated sea-water, which is probably explained by their extra- 
ordinary sensitiveness towards increase of concentration. The parallelism 
of sensitiveness towards cold and concentration points to the accuracy 
of the Miiller-Thurgau theory — namely, that death from freezing is 
caused principally by the abstraction of water consequent in ice-forma- 
tion. The sensitive Trailliella withstood a temperature of -4°C. for 
two hours without the slightest damage, provided no formation of ice 
took place. E. S. G. 
Tyson Collection of South African Marine Algae. — E. M. Delf 
and M. R. Michell (. Annals Bolus Herbarium , 1921, 3. 89-119). ' A 
list of species represented in the herbarium of the late Mr. W. Tyson, 
which is preserved in the Bolus Herbarium and is composed almost 
entirely of specimens from the shores of the Cape Province and Natal, 
chiefly from Algoa Bay, the Kowie, Kei Mouth and the Cape Peninsula. 
Incorporated in the list are personal observations made on dried and 
fresh material. The distribution of the species is affected by the 
difference of temperature of the water on the two sides of the Cape 
Peninsula ; and also probably by the different formation of the fore- 
shore, which has rocks mainly of sandstone on the eastern side and 
often of granite on the west. The algae of the west coast are however 
less accessible, and have been insufficiently studied, making a comparison 
of the two sides at present impossible. E. S. G. 
Algae Mildbraedianae Anrobcnenses — R. Pilger (Engler's Bot. 
Jahrbiich , 1920, 57, 1-14, figs, in text; see also Hedwigia , Beiblatt , 
1921, 62 (88). An account of the marine algae collected by J. 
Mildbraed in 1911 on the island of Annobon off the Guinea Coast, 
West Africa. Seven new species and one new variety are described, 
discussed and figured. Caulacanthus fastigiaius Kiitz. is reduced to a 
variety of C. ustulatus Kiitz. E. S. G. 
