e 
lacustris, were it not for the many, lisht-brown sclerenchyma cells 
of which I have nerer found the least sien in lacustris .Further, the 
dead lobes of the rhizome stand upright as wirh rip,while they usually 
point downward with with lac.The macrospores are not quite ripe. You 
determined them to be 0.53 mm, I find them 0.54 - 0.64,which fits the 
reports for lacustris , but just as well for riparia. Thus,may-be a 
ripariawithout stomata for the future. 
3. I. riparia Differs from I. lacustris through copious stomata, 
Laxrture ° 
and copious, brown sclerenchyma cells and the consistency of the rhy- 
come, but similar in the macrospores. The form from Uxbridee has some- 
what smaller leaves, and the spores come somewhat close to Engelmanri. 
However I consider it definitely a riparia_ ‚because I cannot find a 
siegen of vascular bundles, the same for the one from the Delaware. 
4..I. Tuckermani Diverging from riparia through very small’! leaves, 
sparse, single sclerenchyma cells in the sporansium and the form of 
the macrosvpores. Velum ee half covering,as with riparia.Only 
from one locality, 
S. I. ambierua mihl, or if you arree,Br. & Engelmanni. I have exa- 
mined the specimens of it and the europaean echinospors arain care- 
fully for stomata. I was not able to find a single stoma on any euro- 
paean specimen (Scandinavia, Germany,Beleium,Frarnce, Scotland,Ireland, 
Yemouie *,., and not even for the most northern one from Lapland.. 
But in Iceland the stomata begin, and they are found again in specimens 
from Greenland. from Canada and with all from the United States. One 
needs to examine the tips of the leaves to find them, as they are ab- 
sent further down i.e. 2/3 of the leneth. Only on the dubious speci- 
mens from the Catskill'’Mountains was I unable to find stomata., how - 
ever I must state, that my specimenshage all the leaves bröken off at 
the tips, and, in addition, they are thickly coated with parafin or 
another substance,. With better specimens you will find without doubt, 
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| BOTANICAL 
(efoJe)iglelsi m c-TT-10t7-Te GARDEN 
