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furiously flowing Giant Spring on the bank of the Missouri Riv- 
er, near Great Falls. Several main stems arose from a common 
swollen foot, and branched freely above; a dark sap-green 
when taken from the water, but drying considerably lighter on 
paper. This is the only specimen, thus far, reported from Mon- 
tana, and, like specimens collected by Dr. C. L. Anderson, in 
California, and others from Connecticut, collected by Dr. W. A. 
Setchell, it is very distinct in habit of growth and in general 
appearance from any of our specimens of D. glomerata, in which 
latter the stems and branches are all immersed in a gelatinous 
substance, more or less firm and dense, according to the age of 
the plant, which binds them into a glomerule varying from the 
size of a small pea up to that of an English walnut. In D. plu- 
mosa the plant has the slippery envelope so modified as to leave 
every part free, and the general habit of growth in our specimen 
was similiar to that of reduced forms of Batrachospermum monil- 
tforme, but the other specimens referred to were weaker and 
more diffuse. Giant Spring, banks of the Upper Missouri River, 
near Great Falls, Montana, September, 1885. 
Stigeoclonium tenue, Kg. Habit of growth and general ap- 
pearance similiar to that of small specimens of Cladophora calli- 
coma, but ofa brighter green color. Common all over the State. 
In sheltered nooks it may be found flourishing in winter, but most 
abundant from the middle of May till the middle of July, and by 
the end of the month it has pretty well disappeared. 
Chetophora pisiformis (Roth), Ag. Found but once and 
then attached to dead twigs in a pool of cold water, collected 
from a spring in a dark ravine, at an altitude of about 7,000 feet, 
in the Belt Mountains, July, 1886. In these specimens, the thal- 
lus was half an inch in diameter, and sub-globose. 
Chetophora endiviefolia, Ag. This beautiful species is com- 
mon all over the State, but especially so in those parts of the 
Upper Missouri River, and its more sluggish tributaries having 
muddy bottoms. It grows chiefly in shallow water near the 
shore, and is at first attached tostones. May be found in winter, 
but is at its best during July and August. 
Cladophora fracta, Kg., var. gossypina, Kg. Common in 
ponds, sloughs, and in slow-flowing spring water somewhat impreg- 
