Hapalosiphon major Tilden

Josephine E. Tilden. American Algae.

167. Hapalosiphon major n. sp.

A	Stratum widely expanded, bright aeruginous in color; filaments

sheathed, branched, composed of cells sometimes cylindrical, 3—6 mik.
in width, showing no dissepiments or divided into short somewhat quad-
rate to very long cells, sometimes globose up to 11 mik. in diameter;
branches single or geminate, sometimes geniculate; heterocysts inter-
calated, oblong, cask-shaped, about 8 mik. in width, 1—2 times as long
as wide.

Completely coating bed of very swift mountain rivulet, at vent of hot
spring. Temperature of spring 61° C. Algal growth begins here and
disappears at a distance of 55 feet from spring where temperature is 51°
C. Most luxuriant growth 35 feet from spring at temperature of 54° C.

Mountains near Lower Geyser Basin, Yellowstone National Park.

J. E. T. 28 Je 1896.

The filaments of H. major are nearly twice the diameter of those of H.
laminosu.s. An important character of the latter plant is its habit of
forming crystals of lime, according to Cohn, who studied the plant at
Carlsbad. The Yellowstone species occurred in silicious waters only,
at least it was not discovered at Mammoth Hot Springs, where the wa-
ters contain calcium carbonate.

B.

In hot spring. Temperature 55° C.

forest Grove, Oregon.

^	^	Coll. Francis E. Lloyd, 1895.

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