2 ENGELMANN—THE GENUS ISOETES IN N. AMERICA. [3 $$ 
it his I. macrospora. No date being indicated on the labels, the 
above-mentioned year is a mere guess. 
1825 (?). Jens Vahl collected in Greenland a small Isoetes , 
referred to I. lacustris , which proves to be one of the forms of 
/. echinospora . 
1831. J. W. Robbins gathered an Isoetes near Uxbridge, 
Mass., which I recognize as I. riparia. 
1832. C. J. Moser, who collected for the German Unio itine- 
raria , obtained specimens on the Lehigh river near Bethlehem, 
Pa., and near Philadelphia, both of which were distributed to the 
subscribers as /. lacustris. One of these (in Herb. Bernhardi, 
now in the Herb. Missouri Bot. Garden) represents /. Engel - 
tnanni; another, which I have seen in Europe, is I. riparia. 
1834. Th. Nuttall discovered an Iso&tes on the Columbia river 
in Oregon, which I saw in E. Durand’s Herb, with Nutt all’s own 
label, I. opaca ; it was afterwards named I. Nuttallii. 
About the same year Drummond collected u I. lacustris” on 
the Saskatchawan, according to Hooker’s FI. Bor. Am. ii. 268, 
which I have not been able to compare and to identify. 
1840. J. W. Robbins found I. lacustris near Uxbridge. 
1842. Rugel discovered an Isoetes in Lake Imonia in Florida, 
which was soon afterwards distributed in Europe by Shuttleworth 
under the name of I. flaccida. None of his specimens are be¬ 
lieved to exist in America. 
In the same year N. Riehl and myself found near St. Louis, 
Missouri, the species which from my specimens was by A. Braun 
named I. Engelmanni. 
1843. Chas. Geyer found in Western Idaho I. Nuttallii , ac¬ 
cording to A. Braun, who examined the specimens in the Kew 
Herbarium. 
In the same year S. Tuckerman collected I. lacustris in the 
Echo lake in New Hampshire. 
1844. Wm. Zantzinger rediscovered the Isoetes on the banks 
of the Delaware near Philadelphia. His specimens, sent to me, 
are the type of my I. riparia. 
1845. T. W. Robbins found in Massachusetts I. echinospora , 
var. Braunii. 
1848. E. Tuckermann discovered near Boston the species 
^yhich was by A. Braun named for him I. Tuckermani. 
