ne 
rot 
oe“ 
Jamauts 
any reagents; when I split the small crosscut and remove all “s- 
stE&s carefully, then shavine of the found v wew is rarely neces - 
sary,but can be easier after treatment with potassium.- Spread out 
in this way - as mentioned — the bundles can be seen well,obvious- 
Pamot KA 
ly after removal of vestie and the mt bundles. Also, on 
very thin crosscuts of dried and boiled leaves I saw them well’af- 
thew had been cauterized with potassium. 
On joung plants of this year of Engelmanni they appear very 
sharply. 
Muncata and Boottii I keep in the meanwhile with echinospors, 
the same with Braunii,which considered a species must cede the nane 
to the plant of the tertiary, otherwise, as a form, may well keep it. 
All have very broad velums — have you seen real echinospors from 
Amerika with smaller velums ?°This velum and the regular death and 
annual droppines-off of the tuber of the previous year,seem to me to 
be the principal difference from the europaean form, 
P 
I had sent * and 2. a lot of Lemna with 
many observations of a Mr. Austin, a teacher in New Jersey, whch 
lead him to more exacting observations;he now recognizes the species 
Torreyi and perpusilla, as he writes me in a letter,which arrived to- 
day and he mentions that one cannot see ever flowering Lemnae except 
in mediterranean countries; But beautiful fructification near Neckar- 
au, collected in August 1827, of which I will send him sone. 
I. again, ask about I.Chapmani and flaccida;Nuttallii etc., in 
general for a continuation of your letter,which did not encompass 
the forms with vascular bundles. 
Specifically about the velum of Chapm. and Buttalliji ‚both of 
which I consider totally closed; the latter zpecimen was entirely un- 
ripe, the other is not available to me any more, you and Gray have 
probably the only specimens. I further would like to hear, what yow 
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