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358] TRANS. ST. LOUIS ACAD. SCIENCE. I 
The Genus Isoetes in North A?nerica . 
By Dr. George Engelmann. 
§ 1. History of Isoetes in North America '. 
The Jsoetesy insignificant and apparently sterile as they are, 
were long overlooked or ignored by pur botanists, so that until 
thirty or forty years ago very few specimens were collected, and 
none were distinguished from I. lacustris , if we except NuttalTs 
guess at his Oregon discovery; but the genus has attracted so 
much attention, and lately so many forms have become known, 
that it seems to me an interesting task to trace up the history of 
the discovery of the different species and their varieties, and of 
the area of their distribution, and then the date of their publi¬ 
cation, before I enter into their scientific description. 
1. DISCOVERY. 
1806 (.?). The first notice which we have of an Isoetes in 
North America is given in Pursh’s Flora, ii. 671, where he states 
that u Isoetes lacustris” grows in the bottom of Oswego river, 
near the falls, and adds his v. v., which means that he saw it liv¬ 
ing, and therefore probably found it himself; and as he travelled 
through the regions near the Great Lakes in 1806, it was proba¬ 
bly in that year that he met with it. I have not seen Pursh’s 
specimens, but doubt not but that it will have to be referred to 
I. echinospora , var. Braunii , the only form thus far known from 
Western New York. 
1815* Th. Nuttall collected u /. lacustris ,” abundant along 
the inundated gravelly and miry shores of the Delaware at Gib- 
sonville (now a part of Philadelphia) on Aug. 22d, according to 
the label of a specimen in Collins’ Herbarium, presented to me 
by E. Durand. It proves to be I. riparia . 
1820 ( ?). L. von Schweinitz obtained in the Catskill Moun¬ 
tains in New York I. lacustris; some of his specimens are now 
found in the Herb. Philad. Acad. Natural Science and one in 
the St. Petersburg Imperial Herb. Some of them are labeled 
“ Catskill Mountains” and others “Bethlehem,” the latter, which 
was von Schweinitz’s residence, probably by mistake. One of 
the specimens was loaned by the late Elias Durand—in whose 
possession it was—to Durieu de Maissonneuve, who founded on 
Missouri Botanical Garden 
George Engelmann Papers 
. . Botanical 
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