Bt. Lonia 066.797. 1866 
Dear Braun 
On Sept. 25 I received your last letter and write to you on the 
same day promising to make a decision soon. Three weeks have passed 
and I cannot yet send everything as I have not yet come to a complete 
decisiomIn the meantime I search diligsently material and notes,. the 
latter too for the history of the Isoetes and those in the United 
States; everywhere I find kind acceptance and help. 
Isoetes Braunii has smaller microspores than melanospora and a 
velum, which covers the sporangeium by 2/3 - 3/4 and that with all spe- 
cimens from 6 - 7 localities, which I have examinediand also my old 
Be nereaieen A Dontrast, 15.38 Not entirely certain 
that muricata is different from it; The leaves are larger,erreener, the 
velum a little smaller,but the spores are not always different, often 
mondt 
have seen stomata repeatedly,thouseh mostliy they do not have any; with 
cultivated specimens and wild ones from Niagara, never any othersz 
with muricata with small specimens grow out of water. 
I cannot consider the thick-walled cells in the epidermis of the 
spore-containers as specific; most strikine is the difference between 
specimens of I. Engelmanri collected on the same day in the same swanp 
of which I mailed you 2 leaves during the sommer,one with brown, an 
other (the common form) with white bast.The spore-containers of the 
two are as different as possible in the formation and hardness of 
these cells,so that on that basis the plants could go as varieties, 
You will easily convince yourself with the collected specimens. 
But I.riparia has other and better differences from Engelmanni 
throush the larger spores, which are not scar-like. 
Il. riparia and I.saccherata form a special appearance within the 
Isotes amphibiae, being in estuaries durins flood 1 - 3 feet above 
Water and bared durine ebb - but in sweet water I! Most likely restric- 
9 10 MIıSSOURI 
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