22 ENGELMANN—THE GENUS ISOETES IN N. AMERICA. [379. 
4. I. echinospora, Durieu. One of the smaller species with 10 to 30. 
or 40 soft bright green or sometimes reddish leaves, gradually and regu¬ 
larly tapering from a thick base to a very slender elongated-point abso¬ 
lutely without stomata, 2 to 4 or sometimes 5, inches long; sporangia 
orbicular to broadly oval, unspotted, with a narrow velum; macrospores 
0.40 to 0.50 mm. thick, densely covered with delicate* erect, truncate, or 
slightly forked spinules; microspores 0.030 to 0.034 mm. long, almost 
Smooth.—Bull. Bot.. Soc. Fr. 8, 164. 
Only in Europe from Northern Italy to Germany, France and England,, 
extending to Lapland and Iceland, but apparently not in America. 
Ih this country we have a series of forms which have been distinguished 
by eminent authority, especially on account of the presence of stomata so 
various in number and often so difficult to discover, and of a slight differ¬ 
ence in the form and size of the microscopic spinules which cover the ma¬ 
crospores. I have thought best to unite them specifically with the Euro¬ 
pean type, though it seems strange that in the European plant stomata 
should be absolutely absent, and it must remain subject to individual judg¬ 
ment, if not doubt, which view ought to be preferred. Nearest to the Eu¬ 
ropean true /. echinospora stands the var. Braunii and the other extreme 
is var. muricata, wide-ranging forms of a single type. The same difficul¬ 
ties, the same doubts, and the same solution, we find in studying some 
foreign forms and especially thbse allied to I. velata of the south of Europe. 
* * Stomata few. 
I. echinospora, var. Braunii, Engelm. Rather small, with 13 to 15 
gfeen or reddish-green erect or spreading, rather short (3 to 6 inches long), 
tapering, soft leaves, generally with few stomata towards the tip onl y[ 
sporangia orbicular to broadly elliptical, spotted, generally £ or even f 
covered by a broad velum ; macrospores 0.40 to 0.50 mm. thick, rarely a 
little longer, covered with broad, retuse spinules, sometimes somewhat 
confluent, and then dentate or incised at tip; microspores 0.026 to 0.03a 
mm. long, smooth.—Gray Man. 1 . c. /. Braunii , Durieu 1 . c. 11, p. 101. 
The most common species of our flora from New Jersey and Pennsylva¬ 
nia, northward and northwestward, sometimes on gravelly soil, at other 
places reported from soft mud, in ponds or slow-running streams, also 
near the banks of larger lakes or under the influence of tidewater, nor¬ 
mally submerged from a few inches to several feet, in dry seasons some¬ 
times getting out of water; associated with Eriocaulon septangulare , 
Lobelia Dortmana , Sparganium, Scirpus, Eleocharis , etc. New Jersey : 
in tidewater of Tom’s river, a slender long-leaved form, C. F. Parker 
C. E. Smith, and others; in a lake in Morris Co., T. C. Porter. Pennsyl¬ 
vania: Montrose, Susquehanna Co., A. P. Garber; Great Lake, Pocono 
Mountain, Porter & Canby ; Presque Isle, Erie, A. P. Garber . New York : 
Catskill Mountains in the lake near the hotel, G. W. Clinton; Round Lake 
above Bolton, west of Lake George, on white sand, and in Lake Placide, 
L. Lesquereux ; Luzerne Lake and in Niagara river below Buffalo, G. W+ 
0 1 2 3 4 5 6 7 8 9 10 MissoCjr 
Botanica 
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