100 BOTANICAL GAZETTE [ FEBRUARY 
Stratum aeruginous; filaments often strongly bent; sheath 
not visible; trichomes pale aeruginous, not constricted at joints, 
with apex sharply bent, briefly attenuate and not capitate, 2.5-¥ 
in diameter, the dissepiments generally distinct; articulations 
I.5—2.5 times as long as the diameter; protoplasm commonly 
containing granules; dissepiments sometimes marked by grav 
ules; apical cell acutely conical; no calyptra. 
(az) In overflow of channel. Temperature 49-54.5°C. Will 
Spirulina major. Spasmodic Geyser, Upper Geyser Basin, Ye 
lowstone National Park. W.H. W., 1897. 
This plant is very near typical P. daminosum. The points of 
difference are that the filaments are slightly greater in diametet, 
the apex is almost invariably sharply bent and the dissepimels 
may or may not be marked by granules. Sometimes the entit 
cell contents are granular. 
PHORMIDIUM TENUE (Menegh.) Gomont. Monogr. des Oseill 
in Ann. des Sci. Nat. (Bot.) VII. 16: 169. pé. 4, f- 23-23: - 
Tilden, Am. Alg. Cent. II. no. 182. 1896. (Pz. LX, fig-17-) 
Stratum consisting of a thick firm mass, 10-40" in thic 
ness, upper exposed surface honeycombed, the ridges being 
thin and papery, and easily crushed; in color surface showed? 
range between ferrugineus and ochraceus, the interior betwee 
viridis and prasinus; filaments very long, somewhat straight 
sheath delicate ; trichomes light aeruginous, straight, constrict” 
at joints, the dissepiments themselves generally indistinct, with 
apex straight or sometimes bent, not capitate, 2-3 in eit 
articulations in general 1.5-2 times the diameter, 36.40 7 
length ; protoplasm homogeneous; apical cell acutely cont 
or bluntly rounded ; no calyptra. 
Around edges of spring, not covered by water, vie 
flows in little streams through and around it. Temperat 
water 33°C. Lower Geyser Basin, Yellowstone National 
js Bet, 29 Je 1806. 
watt! 
ure o 
Path 
PHORMIDIUM RUBRUM Tilden, Am. Alg. Cent. I. 9% ae 
1896. (Pl. IX, fig. 78.) - 
