Another field character to identify quillworts *in situ* is to make a cross
section through the microphyll (leaf).... If I am not mistaken there will be
four air chambers in each microphyll, indicating that it's Isoetes, an not a
grass, sedge, rush or other plant of similar morphology and habitat.
I was taught this character on an AIBS fern foray in the Edwards
plateau of Texas where we discovered an Isoetes species in shallow lake
edges (< 0.5 m deep). It can be used to nondestructively ascertain if a
suspected plant is in fact a quillwort. Also check fern field manuals for
other useful characters. The one by David Lellinger is quite good and
includes distribution maps. Dr. Carl Taylor (Milwaukee Natural History
Museum) is one of several resident experts on Isoetes.
HTH,
Rob Wallace
--
Robert S. Wallace
Associate Professor of Botany "In cerevisia veritas est."
Dept. of Botany - Iowa State Univ.
Ames, Iowa 50011-1020 rwallace at iastate.edu FAX: 515-294-1337
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