Jepson eFlora: Taxon page
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Isoetes occidentalis

Higher Taxonomy
Family: IsoetaceaeView Description 

Common Name: QUILLWORT FAMILY
Habit: Perennial herb, aquatic to terrestrial. Stem: buried, corm-like, 2--3-lobed, corky, brown. Leaf: simple, in grass-like tufts, spirally arranged on stem top, erect to spreading, < 30 cm, linear above base.
Genera In Family: 1 genus, 200+ species: worldwide.
eFlora Treatment Author: W. Carl Taylor & Jon E. Keeley
Scientific Editor: Alan R. Smith, Thomas J. Rosatti.
Genus: IsoetesView DescriptionDichotomous Key

Common Name: QUILLWORT

Etymology: (Greek: evergreen, from habit of some species) Note: Perhaps most poorly known lycophyte genus. Mature female spores, found in decaying leaf bases or soil, critical for identification, as are hand lens for texture when dry, microscope with micrometer for size. Hybrids (spores of variable size, shape) common between aquatic species, making them less distinct.

Isoetes occidentalis L.F. Hend.
NATIVE
Habit: Plant underwater. Leaf: evergreen, < 20 cm, rigid, brittle, tapered to tip, dark green; base brown-white. Chromosomes: 2n=66.
Ecology: Persistent lakes, pools; Elevation: > 1500 m. Bioregional Distribution: KR, SNH; Distribution Outside California: to British Columbia, Colorado. Note: Hybridizes with Isoetes bolanderi, Isoetes echinospora. Spores mature late summer.
Synonyms: Isoetes lacustris var. paupercula Engelm.
eFlora Treatment Author: W. Carl Taylor & Jon E. Keeley
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botanical illustration including Isoetes occidentalis

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Citation for this treatment: W. Carl Taylor & Jon E. Keeley 2016. Isoetes occidentalis, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=29404, accessed on April 29, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on April 29, 2016.


Isoetes occidentalis
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© 2015 Steve Matson
Isoetes occidentalis
click for enlargement
© 2015 Steve Matson
Isoetes occidentalis
click for enlargement
© 2015 Steve Matson
Isoetes occidentalis
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© 2016 Dana York
Isoetes occidentalis
click for enlargement
© 2016 Dana York

More photos of Isoetes occidentalis in CalPhotos


Geographic subdivisions for Isoetes occidentalis:
KR, SNH;
Markers link to CCH specimen records. If the markers are obscured, reload the page [or change window size and reload]. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.
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map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).

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Data provided by the participants of the Consortium of California Herbaria.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.