3 8 o] 
TRANS. ST. LOUIS ACAD. SCIENCE. 
23 
Clinton ; at the head of Goat Island, Niagara, between stones, G. Engel - 
mann ; Oneida Lake, J. A. Paine ; in Oswego river, F. Pursh, probably 
(see p, 353). Massachusetts : Mystic Pond near its lower end, gregarious 
in soft mud in 1 foot of water, also in other parts of the same pond, and in 
Spot, Spy and Horn ponds, on sandy bottom, all near Boston, W.Boott; 
Hammond’s Pond, W. G. Farlow ; Concord brook, gregarious, on firm 
bottom, 77 Mann; Beaver Pond near Beverly, J. L. Russell; Uxbridge, 
in Grafton Pond and several other ponds, 7 . W. Robbins. Vermont: Mt. 
Mansfield, in the Lake of the Clouds, C. G. Pringle , 77 Mann , on gravelly 
bottoms, 1 to 2 feet deep; Lake Dunmore, A. W. Chapman. New Hamp¬ 
shire : Lake Winnipiseogee, in mud with Gratiola aurea , Eriocaulon , etc., 
G. Engelmann (these specimens were the types of Durieu’s 7 , Braunii ), 
H. Mann , W. Boott; .Echo Lake in the Franconia Mountains (where Mr. 
Tuckerman and myself had found I. lacustris ), W. Boott. Maine : Moose 
Lake on Kennebunk river, C. E. Smith. Nova Scotia, Shelburne, T. P. 
James. Greenland, in the south, “ Tessermint,” 7 . Vahl (perhaps this is 
the true 7. echinosfiora; I could npt well analyze the small and poor spe¬ 
cimen in my possession}. Westward the species has been found in West¬ 
ern Canada (Ontario) near Hastings and in a lake northeast of Belleville, 
on a muddy bottom, j. Macoun. Michigan : Bellisle in Detroit river, H. 
Gillman. Utah : Lake at the head of Bear river in the Uintah Mountains, 
at 9,500 feet alt., S. Watson ; this is tfye most western and highest, quite 
isolated, locality known, to me. 
This form is most closely connected with the European type; the leaves 
are perhaps not quite so finely tapering; sjtomata can always be found, at 
least near the tip of the leaf; the sporangia, white in the type, are spotted 
with brown sclerenchym cells; the macrospores I cannot distinguish either 
in size or sculpture; the microspores I find a little smaller. I may state 
here that the name of 7 . Braunii ^preoccupied, as it has already been 
given to one of the two species of the Tertiary deposits, the well marked 
spores of which have been discovered in the German Brown Coal strata; 
Prof. Braun therefore proposed for our plant, if it should eventually be 
considered distinct, the name of 7 . ambigua« 
Var. robusta, Engelm., similar to the last, but much stouter, with 25 to 
70 leaves, 5 to 8 inches long, with abundant stomata all over their surface; 
velum covering about one-half of the large, spotted Sporangium; macro- 
spores 0.36 to 0.55 mm. thick, with the sculpture of the last ; microspores 
the same as in last. 
In Lake Champlain, on the north end of Isle La Motte, on a firm sandy 
soil with silt, in 1 to 2 feet of water, C. G. Pringle. Larger and stouter 
than any form of the last, but principally distinguished from it by the abun- 
i dance of stomata. 
Var. Boottii, Engelm. 1 . c. Leaves erect, soft, bright green, fewer (12 
to 20) short (4to 5 inches long) ; stomata, mostly few, near the tip; spo¬ 
rangia nearly orbicular, pale-spotted, § or more covered by the broad 
velum; macrospores 0.39 to 0.50 mm. thick, with longer and slenderer 
