24 ENGELMANN—THE GENUS ISO ETES IN N. AMERICA. [381 
delicate, generally simple spinules; microspores 0.026 to 0.030 mm. long. 
—/. Boottii, A. Braun in lift. 
Near Boston, in the Round Pond, Woburn, 2 to 3 feet underwater, and 
in the brook of Tofit Swamp, Lexington, sometimes out of water, Wm. 
Boott . Very striking on account of the delicate green color of its soft 
leaves, and the long and slender spinules of the spores. 
Var. muricata, Engelm. 1. c. Leaves (15 to 20) long (6 to 12 inches'), 
flaccid, bright green, with very few stomata; sporangium broadly oval, 
pale-spotted, about half covered by the velum; macrospores a little larger 
(0.40 to 0.58 mm. thick), with shorter and more confluent, therefore some¬ 
times almost crest-like spinples : macrospores slightly rough on the edges, 
0.028 to 0.032 mm. long.— I. muricata , Durieu 1 . c. 
In the shallow and more rapid parts of Woburn creek, and in Abajona 
river, the main source of Mystic Pond, near Boston, scattered over a 
clean gravelly bottom and always submerged, W. Boott. Remarkable 
for its long flaccid leaves and the shorter spinules of the macrospores, 
which form sometimes crests so that Durieu could compare it with I. 
rip aria. 
5. I. Bolandbri, Engelm. One of the smaller species with erect, soft, 
bright green leaves tapering to a fine point, 5 to 20 or 25 in number, 2 to 
4i inches long, with thin walls and partitions, and generally not many 
stomata; sporagium broadly oblong, mostly without any spots, with a 
narrow velum; ligula triangular; macrospores 0.30 to 0.40 or rarely 0.45 
mm. thick, marked with minute low tubercles or warts, rarely confluent 
to wrinkles; microspores 0.026 to 0.031 mm. long, generally spinulose; 
rarely, in the Rocky Mountain form, smooth, deep brown.—Am. Natural¬ 
ist, 8, 214.—/. Californica Engelm., name only in Gray Man. 1 . c. 
A western mountain species, found gregarious in ponds and shallow 
lakes of the Sierra Nevada of California, northward to the Cascades and 
eastward to the Rocky Mountains : in little pools on meadows in the upper 
Tuolumne valley 9,000 to 10,000 feet alt., on Mt. Dana, on the Mono trail, 
in Mary’s Lake near the summit, 7,000 feet alt., in small lakes about 
Cisco 4 500 to 5.000 feet alt, “mostly gregarious in mud covering gravel, 
in 1 or 2 teet of water,” H. Bolander ; Ice Lake, near Soda Spring station, 
7,500 feet alt., with Menyanthes trifoliata, Engelmann; in many lakes of 
the high sierras, reported by A. Kellogg; on Mt. Adams, Washington 
Terr., W. N. Suksdorf, in the soft muddy bottom of a shallow pond near 
the falls of the Yellowstone river in Wyoming, nearly covering the muddy 
bottom, partly emerged near the banks, C. C. Parry; in a subalpine lake 
at Alta, Wasatch Mountains, Utah, M E. Jones, and in a lake in the 
Gunnison region, Western Colorado, covering ten acres of ground with 
Menyanthes , T. S. Brandegee -This species has much the appearance of 
I. echmosfora var. Bootti, with its soft bright gnlen leaves; the stomata 
are often difficult to make out. 
