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 howellii


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 howellii Engelm.
NATIVE
Habit: Plant becoming terrestrial. Leaf: deciduous, < 30 cm, rigid, not brittle, tapered to tip, bright green; base +- brown to black. Sporangia: membrane covering < 75%; male spores 0.025--0.035 mm, brown in mass; female spores 0.3--0.5 mm, ridged. Chromosomes: 2n=22.
Ecology: Vernal pools, lake margins; Elevation: generally < 1500(2900) m. Bioregional Distribution: KR, NCoR, CaR, SNF, n SNH, GV, CCo, SnFrB, SCoR, SCo, PR; Distribution Outside California: to Washington, Montana, Utah. Note: Small plants of SCo, Washington, Baja California (leaf < 10 cm, female spore < 0.42 mm) are assignable to Isoetes howellii var. minima (A.A. Eaton) N. Pfeiff., recognition of which remains questionable pending further research, although it is +- clear that it should not be treated as an infraspecific taxon of Isoetes howellii. Spores mature late spring, summer.
Jepson eFlora Author: W. Carl Taylor & Jon E. Keeley
Jepson Online Interchange

Previous taxon: Isoetes echinospora
Next taxon: Isoetes nuttallii

Name Search

Botanical illustration including Isoetes howellii

botanical illustration including Isoetes howellii

Contact/Feedback

Citation for this treatment: W. Carl Taylor & Jon E. Keeley 2012, Isoetes howellii, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=29392, accessed on July 19, 2019.

Citation for the whole project: Jepson Flora Project (eds.) 2019, Jepson eFlora, http://ucjeps.berkeley.edu/eflora/, accessed on July 19, 2019.

Isoetes howellii
click for enlargement
© 2007 Neal Kramer
Isoetes howellii
click for enlargement
© 2004 Carol W. Witham
Isoetes howellii
click for enlargement
© 2013 Vernon Smith
Isoetes howellii
click for enlargement
© 2007 Neal Kramer

More photos of Isoetes howellii in CalPhotos



Geographic subdivisions for Isoetes howellii:
KR, NCoR, CaR, SNF, n SNH, GV, CCo, SnFrB, SCoR, SCo, PR
MAP CONTROLS
1. You can change the display of the base map and layers by clicking on the layer control box in the upper right-hand corner.
2. California county polygons can be turned off and on in the layer control box.
3. Filling of Jepson subdivision polygons can be turned off and on in the layer control box.
4. Moving the cursor over any numbered cluster will show the range boundary of the included specimens (with a blue polygon).
5. Marker clustering can be turned off by clicking this link:      Marker Clustering OFF
WARNING: Turning this off might cause maps with large numbers of specimens to load slowly.
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).





 

View elevation by latitude chart


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.