Key to Isoetes
View taxon page for Isoetes
(For a list of species in Isoetes, use the above link.)
Jepson Manual glossary definitions can be seen by moving your cursor over words underlined with dots.
1. Plant terrestrial (or becoming so), of seasonally wet soil, lake
margins, temporary streams,
vernal pools; generally < 1500 m
2. Translucent membrane covering < 75% of
sporangium 
In non-seed plants, a case or sac in which spores are produced, and from which they are released.
..... I. howellii 2' Translucent membrane covering > 75% of sporangium
3. Plant of wet soil;
leaf 
Organ arising from a stem, generally composed of a stalk (petiole) and a flat, expanded, green, photosynthetic area (blade); distinguished from a leaflet by the presence in its axil of a bud, branch, thorn, or flower; sometimes with lateral, basal appendages (stipules); either simple (toothed, lobed, or dissected but not divided into leaflets) or compound (divided into leaflets).
generally > 8 cm, > 1 mm wide at middle, rigid, ± brittle
..... I. nuttallii 3' Plant of vernal pools; leaf generally < 8 cm, < 1 mm wide at middle, soft, flexible
..... I. orcuttii 1' Plant underwater in
persistent lakes or pools; generally > 1500 m
4' Female spores ridged or tubercled
5. Leaf abruptly
tapered 
Gradually (not abruptly) narrower or smaller at base or tip.
to tip; female
spore 0.3–0.5 mm diam
..... I. bolanderi
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Citation for the whole project: Jepson Flora Project (eds.) . Jepson eFlora, https://ucjeps.berkeley.edu/eflora/ [accessed on ]
Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on .
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