go 5 BOTANICAL GAZETTE [ FEBRUARY 
Mastigonema.”* He describes a specimen of New Zealani 
sinter from the hot waters of Rotorua, and notes that “the | 
exact counterpart of this sinter occurs at many localities in th 
geyser basins of the Yellowstone, notably about the Prismatic 
Spring and the overflow channels of Old Faithful. It forms 
over one-half of the section of fifteen feet of sinter exposed il 
the crater walls of the Excelsior Geyser. This sinter we know 
to be the result of the growth and incrustation of little alge 
which form a cedar-colored (Calothrix gypsophila Kg.), or olivt 
( Mastigonema thermale) slippery coating on the surface of the 
deposit. The analogy is so perfect that there seems but little 
doubt that the New Zealand sinter is the result of the growth 0! 
similar or allied algze,’’3 
The plant Calothrix sypsophila (Dichothrix gypsophila) is* 
lime-encrusting form. I have not personally observed it up" 
this time in material from Yellowstone Park. Mastigonema ther 
male, a synonym of Calothrix thermalis, does not characteristical) | 
secrete lime. The Yellowstone form has only been found ! 
siliceous waters. It differs slightly from the type description # | 
Bornet and Flahault in that the articulations, instead of bei 
‘“‘diametro equalibus vel usque ad 3-plo brevioribus” are equal . 
to up to three times longer than the diameter. It agrees, how | 
ever, in this character with Hauck and Richter’s specimen | 
Phyk. univ. no, 742, which was collected from the Carlsbie 
Springs in 1894 and 1895 by S. Schmula. Therefore the t#” 
forms named by Mr. Weed are considered to be the | 
plant. 3g 
The above Species has been described from Carlsbad, i | 
many, by Schwabe, Kiitzing, and Cohn. & 
eT 
ee eT ree ae oe en 
RIVULARIA HAEMATITES (DC.) Ag. Syst. Alg. 26. 1824- eg 
IX, figs. 6, 7, 8, 9.) a 
Ee Thallus forming a hard calcareous crust, 5™™ in thid 
aments dense, 78+ 1.7# in diameter ; sheath narrow, hy@ 
tarely brownish ; trichomes 3.9-5.2u in diameter, with ent 
* Loc. cit. 
3 Loc. cit. 674. 
