Jepson eFlora: Taxon page
Vascular Plants of California
Key to families | Table of families and genera
Previous taxon Index to accepted names and synonyms:
| A | B | C | D | E | F | G | H | I | J | K | L | M |
| N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
Next taxon


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. 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 occidentalis L.F. Hend.
NATIVE
Habit: Plant underwater. Leaf: evergreen, < 20 cm, rigid, brittle, tapered to tip, dark green; base brown-white. Sporangia: membrane covering < 50%; male spores 0.035--0.045 mm, gray in mass; female spores 0.5--0.7 mm, ridged, tubercled. 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.
Jepson eFlora Author: W. Carl Taylor & Jon E. Keeley
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)

Previous taxon: Isoetes nuttallii
Next taxon: Isoetes orcuttii

Name Search

Botanical illustration including Isoetes occidentalis

botanical illustration including Isoetes occidentalis

Contact/Feedback

Citation for this treatment: W. Carl Taylor & Jon E. Keeley 2012, Isoetes occidentalis, in Jepson Flora Project (eds.) Jepson eFlora, https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=29404, accessed on June 25, 2022.

Citation for the whole project: Jepson Flora Project (eds.) 2022, Jepson eFlora, https://ucjeps.berkeley.edu/eflora/, accessed on June 25, 2022.

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

More photos of Isoetes occidentalis in CalPhotos



Geographic subdivisions for Isoetes occidentalis:
KR, SNH
MAP CONTROLS
1. You can change the display of the base map layer control box in the upper right-hand corner.
2. County and Jepson Region polygons can be turned off and on using the check boxes.
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).





 

Data provided by the participants of the  Consortium of California Herbaria.
MAP LEGEND
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.
READ ABOUT YELLOW FLAGS


CCH collections by month

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).