et 
For me you mentioned only the names and locality of plants,.but 
for H. Mann” you gave a description or the most impotent charac- 
teristics,which I have received from him. Thereby you speak of 
thickwalled, brown cells of the sporangium. None of my specimens 
have those; all have thin-walled cells; but Braunii have such cells, 
mixed with clear ones, partially entirely clear; no riparia exan- 
ined by me has cells with such thick brown walls, so that the 
seeds disappear almost; brown and light cells are mixed. 
I['wrote you recently so much that I do not have material for 
more, and little time. 
One more item. Could not flaccida be finallyvonly a sub - 
merged form of Engelmanni (or valida) ?Valida has mostly smaller spo- 
res than Eneelmanni and thornier microspores. I have a foot-long 
Eneelmanni with small tuber from New England totally submerged,hich 
T considered earlier as flaccida.May-be, that's what it is.- You must 
examine it very carefully. No specimen can be obtained directly from 
Shuttleworth. 
What diagnostical importance do you assign to the size of the 
velum ? I believe, that I have said already, that macrospora is not 
only different from ..........throush larger macrospores and smaller 
microspores, but also throueh a velum,which hangs lower. 
Have you seen I. Tuckermani collected by Boott ? He collected 
for me specimens from Mystic Pond at different time in different 
years; I examined all individually and all are Braunii. 
Next fall I hope to come to Germany after Cholera has been over- 
come, as without any doubt it will agaln pursue us, with my family, to 
bringe Georg to a university, and after a year or so my wife and I 
will return here. George should or will study medicine,sSOo as to be 
able to practite professionelly; should he show a specific inclina- 
tion towrad the NaturälSciences,it would please me, if he would de - 
7 10 MISSOURI 
| . | _ BOTANICAL 
