241 
ON SOME ALGA| FROM HOT SPRINGS. 
By G. 8. Wesr, M.A., F.L.S. 
ee 439.) 
T 
blue-green a or ued These alge are of particular 
interest on account of the manner in which they assist in the 
deposition of considerable quantities of calcareous fincronta and 
siliceous sinter. The formation of rock-masses by the agency’ st 
hot waters; and, although numerous people had noticed the oc- 
currence of algal growths in tat ch situ ations, up to that time, few 
careful observations had been made with regard to the specific 
nature of the plants which pe the construction of ni -spring 
eposits. 
In referring to the occurrence of hot-water growths in such 
widely- bepainicd localities as Iceland, the Azores, New Zealand, 
Japan, and the United States, Weed remarks that ‘the flora is 
Species themselves being identical to a great e t.” 1s 
Cannot altogether agree ; ven the few collections from 
Iceland have a are diverse sere and the nu of species 
teed and | Masse ce Celt, are present in the 
Collections I have examined from Iceland. Miss J. E. Tilden} 
has also specifically examined some algw from the geysers of the 
ae teen National Park, U.8.A., and, of the species she records, 
0 ‘ ath midium laminosum (Ag.) Gomont, is present in the 
celand material. 
The SSthest temperature at which alge will exist is said to be 
94°5° C. (20 0° F.). This was observed by Brewer§ in California. 
From Iceland, 85° C. (185° F.) was the highest femperature of the 
* W. H. Weed, ‘Formation of Travertine and a Sinter by the 
pinion of Hot Springs, ” Rep. U.S. Geol. Survey, 188 
Schmidle, “Ueber die tropische afrikanische fe ication,” 
Roger ot Jahrbiichern, 1901, Bd. 30, He 1 
SS E. Tilden, “On some — Stalactites of the Yellowstone Nationa 
ak Bee Gazette, xxiv. no. 3, 1897. 
W. H. Brewer in Amer, Journ. Science, ser. 2, xi. 
Journat or Borany.—Vou. 40. (Juxy, 1902. | € 
