Nuttall's Quillwort
Isoetes nuttallii
Synonyms: Isoetes nuttallii var. nuttallii, Isoetes opaca, Isoetes suksdorfii

Nuttall's quillwort as found in vernally moist prairies on Department of Natural Resources lands at the southeastern corner of Clark County, WA........May 21, 2016.
Paul Slichter