1911] Collins,— Notes on Algae 185 
distribution in this way, delicate pink dots were found on some of 
the fronds, which proved to be formed by this Dermocarpa, appar- 
ently new, which I have named for Miss Vickers, whose work will 
always be of value to American algologists. The volume of beautiful 
plates, published after her death, represents that part of the work 
she had planned which was enough advanced for publication. 
CALOTHRIX KaAwnarskvr Schmidle, Algen aus den Hochseen des 
Kaukasus, p. 9, 1897. According to the description by Schmidle, 
this alga forms rather dense tufts, .50 to .75 mm. high, the trichomes 
about 4 u thick in the middle, tapering upwards into a long, slender 
hair, and suddenly thickened at the base, ending in a wider, hemi- 
spherical to ovoid heterocyst; cells varying from one half to one and 
one half diam. long, blue-green; sheath close, thin and hyaline. This 
species comes near to C. Braunii Born. € Flah., but is of much smaller 
dimensions in every way. 
It is of interest as showing the cosmopolitanism of the smaller 
fresh water algae, that this species, first found in the Caucasus moun- 
tains in 1897, should have appeared in 1906 in a tank in the Physical 
Laboratory of the University of California, and in 1910, attached to 
various algae in brooks in Illinois. To Schmidle’s description can 
now be added, Spores 4-5 u diam., 2-4 diam. long, singly, rarely two, 
above the heterocyst. This is the fifth species of Calothrix for which 
spores have been recorded, out of the 42 species recorded by Forti,! 
excluding doubtful forms. The genus is distributed all over the 
world, both in fresh and in salt water, but is much more abundant 
in the latter; the spore-bearing species, however, are confined to fresh 
water; one, C. crustacea, is normally marine, but is recorded as produc- 
ing spores only when cultivated in fresh water. "This seems reasonable 
when we remember that spores of this character are contrivances for 
perpetuating the species over periods of drought, when all the vegeta- 
tive parts would perish. The Calothrix species are specially plants 
of warm, shallow water; small pools and brooks are often dry in sum- 
mer, while in deeper bodies of water the decrease in depth would lay 
bare the region near the shore where Calothrix would most abound. 
The sea level, on the other hand, is practically the same from day to 
day and year to year; the marine Calothrix species usually grow 
attached to larger plants or in tide pools, and continuously im- 
! Forti, Sylloge Myxophycearum, Vol. V of De Toni, Sylloge Algarum, Padova, 
1907. 
