386 SUMMARY OF CURRENT RESEARCHES RELATING TO 



a description of every tribe, genus, species, and variety, with keys and 

 numerous figures. The text is in Danish. 



Moss Exchange Club.* — W.Ingham publishes the twentieth annual 

 report of the Moss Exchange Club, containing lists of the mosses ami 

 hepatics collected by and distributed among the members. Critical notes 

 on the specimens arc appended ; also a new key to Thuidium recognition 

 and its allies, by H. N". Dixon, is included. 



Thallophyta. 



Algse. 

 (By Mrs. E. S. Gepp.) 



Algae of Hampstead Heatli.f — E. M. Delf reports on the algal vegeta- 

 tion of a series of eight ponds, connected with one another, on Wylde's 

 Farrn, Hampstead Heath. A table is given of the species observed in 

 the whole series of ponds, together with the number of occurrences 

 noted between January, 1912, and March, 1914. The author tinds that 

 there is a well-marked periodicity in the occurrence of the majority of 

 the alga? in these ponds. The season of greatest diversity and abun- 

 dance was from February to April or May in the years recorded. This 

 corresponds to a period of variable rainfall, gradually ascending tempera- 

 tures, increasing light intensity, and of comparatively slight development 

 of animal life. As the temperature rises from May to July the algaa 

 become greatly diminished, and many forms altogether disappear until 

 late in the following October or earlv November. In 1912 there was 

 a secondary maximum in October and November, falling off again in 

 December and January ; but in 1913 there was a slight increase in 

 December, and an apparently stationary condition in January prior to 

 the early vernal maximum (January to March) which followed. The 

 Protococcales and Ulotrichales are dominant somewhat prior to the 

 Conjugate and Heterokontas, the Conjugate dominating every other 

 form in April and May. One species of Spirogyra is described, which is 

 apparently a summer form. 



Algological Notes on the Hohe Tatra.J— A. Scherffel describes 

 two new forms of already recorded fresh-water alga', and adds four new 

 Hungarian records in a list of species from the Hohe Tatra. 



Algae Stalactites in Bermuda. §— J. W. Harshberger describes the 

 formation of stalactites in the Devil's Hole, Bermuda, caused by the 

 activity of certain species of algas in removing CO J from the water, and 

 thus bringing about the deposit of the limestone. The species in question 

 are Ghrootheca Ricteriana, Gleocapsa aeruginosa, G\ gelatinosa, G. quater- 

 nata and GUotheca linearis. 



* York : Coultas and Volans, Ltd., 1915, pp. 117-44. 

 + New Phytologist, xiv. (1915) pp. 63-80 (tigs.). 

 ; Magyar Bot. Lapok, xiii. (1914) pp. 189-93. 

 § Torreya, xiv. (1914) pp. 195-7. 



