Jepson eFlora: Taxon page
Vascular Plants of California
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Isoetes bolanderi

Higher Taxonomy
Family: IsoetaceaeView Description 
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. Sporangia: solitary, embedded in wide leaf base, < 1 cm, +- covered by a translucent membrane, male or female; male spores > 10000, < 0.045 mm, +- bean-shaped, gray or brown in mass; female spores 20--200, 0.2--0.7 mm, spheric, white, +- smooth, ridged, tubercled, or prickly.
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 bolanderi Engelm.
Habit: Plant underwater. Leaf: deciduous, < 20 cm, rigid, not brittle, abruptly narrowed to tip, bright green; base white to +- brown.F Sporangia: membrane covering < 30%; male spores 0.02--0.03 mm, brown in mass; female spores 0.3--0.5 mm, ridged, tubercled. Chromosomes: 2n=22.
Ecology: Persistent lakes, pools; Elevation: > 1300 m (250 m in Marin Co.). Bioregional Distribution: KR, NCoRH, CaRH, SNH, SnFrB, SnBr, Wrn; Distribution Outside California: to British Columbia, Wyoming, New Mexico. Note: Hybridizes with Isoetes echinospora, Isoetes occidentalis. Spores mature late summer.
Synonyms: Isoetes bolanderi Engelm. var. bolanderi; Isoetes bolanderi var. pygmaea (Engelm.) Clute
Jepson eFlora Author: W. Carl Taylor & Jon E. Keeley
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)

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Next taxon: Isoetes echinospora

Botanical illustration including Isoetes bolanderibotanical illustration including Isoetes bolanderi

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Citation for this treatment: W. Carl Taylor & Jon E. Keeley 2012, Isoetes bolanderi, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on July 20, 2024.

Citation for the whole project: Jepson Flora Project (eds.) 2024, Jepson eFlora,, accessed on July 20, 2024.

Isoetes bolanderi
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©2006 Steve Matson
Isoetes bolanderi
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©2021 Michael Charters
Isoetes bolanderi
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©2006 Steve Matson
Isoetes bolanderi
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©2007 Steve Matson
Isoetes bolanderi
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©2016 Dana York

More photos of Isoetes bolanderi
in CalPhotos

Geographic subdivisions for Isoetes bolanderi:
KR, NCoRH, CaRH, SNH, SnFrB, SnBr, Wrn
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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 occurrence).


Data provided by the participants of the  Consortium of California Herbaria.

View all CCH records
All markers link to CCH specimen records. The original determination is shown in the popup window.
Blue markers indicate specimens that map to one of the expected Jepson geographic subdivisions (see left map). Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.

CCH collections by month Flowering-Fruiting Monthly Counts

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa, if there are more than 1 infraspecific taxon in CA.
Blue line denotes eFlora flowering time (fruiting time in some monocot genera).