Page author: Hattie Palmer
Isoetes howellii
Howell's quillwort

Origin: Native

Conservation Status: Review Group 1 in Washington (WANHP)


Perennial herb, aquatic to terrestrial; rootstock buried and corm-like, nearly globose, with 2 lobes, corky, brown.


Leaves deciduous, simple, in tufts somewhat resembling grass, spirally arranged on top of stem, erect to spreading, rigid but not brittle, up to 25 cm, linear above base, tapered to apex, bright green with pale to brown or shiny black base.


Sporangia solitary, embedded in enlarged leaf base, less than 1 cm, less than 3/4 covered by a translucent membrane, male or female; male spores less than 10,000, 0.025-0.035 mm, somewhat bean-shaped, brown in mass; female spores 20-200, 0.3-0.5 mm, spheric, white, ridged.

Accepted Name:
Isoetes howellii Engelm.
Publication: Trans. Acad. Sci. St. Louis. 4: 385. 1882. 1882.

Synonyms & Misapplications:
Isoetes melanopoda Gay & Durieu var. californica A.A. Eaton
Isoetes nuda Engelm.
Isoetes underwoodii L.F. Hend.
Additional Resources:

PNW Herbaria: Specimen records of Isoetes howellii in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Isoetes howellii checklist entry.

E-Flora BC: Isoetes howellii atlas page.

CalPhotos: Isoetes howellii photos.

USDA Plants: Isoetes howellii information.

9 photographs:
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