Notes on Isoetes riparia and Isoetes saccharata. 
T. CHALKLEY PALMER. 
DISTRIBUTION.—In the middle states both these species 
are accounted quite local. Farther north 7. riparia Engelm. 
is recorded as coming from several places, but south of New 
England it is apparently confined to the tidal shores of the 
Delaware river.!| So far as known, /. saccharata Engelm. 
is still more restricted in its range; and, in fact, it had been, 
until quite lately, collected only by Wm. M. Canby, its dis- 
coverer, within quite circumscribed areas on the two neigh- 
Spores 0.40 to 0.47™ thick, covered with very minute 4! 
or sometimes a little confluent warts; microspores paP! 
0.024 to 0.028™™ long. 
1 Engelmann: Trans. St. i i, 4: 
*Engelmasa. or Louis Acad. Sci. 4: 382. 
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