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Var. genuina, Kirch, is plentiful in all pure, cool, rapid waters 
of the state; found in the mountainestreams, at the altitude of 
8,000 feet. Same duration as the species. 
Var. FILAMENTOSA, Anders. and Kelsey n. var. Similar to 
the last but easily distinguished by the more or less numerous 
elongated simple or sub-simple filaments rising above the other 
branches and crowned by several to many short-fasciculate to 
sub-corymbose penicillate branchlets. Plants bright green, I to 6 
inches high, arising from a calcareous foot, which adheres strongly 
to the rocky substratum. Cataracts of the Missouri and other 
rivers of the state; also at Niagara Falls (Wolle), June to October. 
Var. pumila, Bailey. Frequent on wet wood-work of flumes 
and races at the city of Great Falls. This pretty little variety 
grows like a miniature bush, dark green in color, changing with 
age to a dull dirty green. None of our specimens are over half 
an inch high. August to November. | 
Vaucheria sericea, Lyngb. Abundanteverywhere. Delights 
in covering the flat stones and bed-rock of turbulent streams, ap- 
pearing like big patches of a dense, bright green turf. Also 
grows in the mud along the margins of springs. All the year 
round, but at its best from July to December. 
Vaucherta sessilis (Vauch), D.C. var. c@spitosa (Vauch), Ag. 
Very common on muddy bottoms of irrigating ditches and on the 
wet ground bordering creeks and springs. July to October. 
Volvox globator, Linn. This curious and beautiful plant is 
found abundantly in ponds and slow streams throughout the 
state, alisummer. 
Protococcus viridis, Ag. and several forms or varieties (?) found 
everywhere on trees, logs and on the stems of dead herbaceous 
plants. One form is particularly partial to charred wood of any 
kind, on which it forms into numerous families by sub-division, 
appearing like roundish grains or masses of greenish pollen to the 
unaided eye. 
Hydrurus fetidus (Vill.), Kirch. Very abundant in the 
Prickly Pear Creek, in Prickly Pear Cafion. Collected but once, 
April 19, 1887. Specimens vigorous. As many as twenty- 
seven distinct main stems were counted rising from a common 
disk of attachment. Plants from six to eighteen inches long, 
