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Vascular Plants of California
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Utricularia macrorhiza

Higher Taxonomy
Family: LentibulariaceaeView DescriptionDichotomous Key
Habit: Annual, perennial herb, carnivorous, of moist or aquatic habitats. Stem: caudex or stolon, then often with thread-like branches. Leaf: simple, in rosette, or simple or dissected, emerging from caudex or stolon, with minute, carnivorous bladders +- throughout. Inflorescence: raceme or 1-flowered, scapose. Flower: bisexual; calyx lips 2[4], upper 3-lobed, lower 2-lobed, or lips unlobed; corolla 2-lipped, spurred at base, lower lip flat or arched upward, blocking throat or not; stamens 2, epipetalous; ovary superior, chamber 1, placenta generally free-central; stigma unequally 2-lobed, +- sessile. Fruit: capsule, round, 2-valved, circumscissile, or irregularly dehiscent. Seed: generally many, small.
Genera In Family: 3 genera, 330 species: worldwide, especially tropics.
eFlora Treatment Author: Barry A. Rice
Scientific Editor: Thomas J. Rosatti.
Genus: UtriculariaView DescriptionDichotomous Key

Habit: Carnivorous by bladders (here treated as modified leaves), into which small organisms are sucked when hairs at opening are triggered [epiphytic]. Stem: submersed or subterranean shoots [rarely caudex]; some aquatic species produce 2 kinds of stems, green (in water or at surface; leaves with flattened or thread-like segments; bladders 0--few) and white (generally buried in substrate; leaves 0; bladders many), the latter not always present in poor collections. Leaf: simple or generally dissected into narrow segments, alternate on stolon, margins often with bristles (visible at 10--30×). Inflorescence: raceme or 1-flowered, emergent; scape slender or wiry, bracts present. Flower: calyx lips 2[4], unlobed; corolla yellow [or not], with red-brown streaks or not, upper lip +- entire, lower entire or 3-lobed, spurred; rarely cleistogamous. Fruit: capsule.
Etymology: (Latin: little bag, from bladders) Note: Size variable, often unreliable for identification; distinction between stems, leaves uncertain. Glands inside bladders consist of 2 pairs of oppositely directed arms, angles of divergence between which used (at 150× or more) to identify fresh or pressed specimens.
Reference: Taylor 1989 Kew Bull Add Ser 14:1--724
Utricularia macrorhiza Leconte
Habit: Floating aquatic. Stem: well defined, weakly branched central stolon with leaves, bladders; winter buds 1--2 cm, bristly. Leaf: 15--90 mm, 1--2-parted at base, each part unequally pinnately dissected above; ultimate segments dense, 30--150, thread-like, margin bristles 0.1--0.3 mm; bladders near base larger than those near tip. Inflorescence: 5--20-flowered; peduncle 1--4 dm, stout, 1--3 mm diam; pedicel recurved in fruit. Flower: corolla 1--2 cm; lower lip > upper; cylindric spur +- hooked upward near tip. Fruit: circumscissile. Seed: 4--6-sided, -winged. Chromosomes: 2n=+-40.
Ecology: Quiet, shallow or deep, rarely flowing, acidic waters; Elevation: < 2700 m. Bioregional Distribution: NW, CaR, SN, SnFrB, SnBr, GB, w DMoj; Distribution Outside California: North America except extreme southeastern, northeastern Mexico, eastern Asia. Flowering Time: Jun--Sep Note: Utricularia vulgaris L. excluded by recircumscription.
Synonyms: Utricularia vulgaris L. var. americana A. Gray; Utricularia vulgaris subsp. macrorhiza (Leconte) R.T. Clausen
Unabridged Note: Plants with floating, inflated, radiating branches at peduncle base, deeply 3-lobed lower corolla lip belong to Utricularia inflata Walter, native to and of special concern in eastern United States, troublesome weed in Washington, presently known only from pond in zoo near Fresno but in future expected in wildlands in California.
Jepson eFlora Author: Barry A. Rice
Reference: Taylor 1989 Kew Bull Add Ser 14:1--724
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)

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Botanical illustration including Utricularia macrorhiza

botanical illustration including Utricularia macrorhiza

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Citation for this treatment: Barry A. Rice 2012, Utricularia macrorhiza, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on December 07, 2023.

Citation for the whole project: Jepson Flora Project (eds.) 2023, Jepson eFlora,, accessed on December 07, 2023.

Utricularia macrorhiza
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©2009 Barry Rice
Utricularia macrorhiza
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©2006 Barry Rice
Utricularia macrorhiza
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©2009 Barry Rice
Utricularia macrorhiza
click for enlargement
©2009 Barry Rice
Utricularia macrorhiza
click for enlargement
©2009 Barry Rice

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Geographic subdivisions for Utricularia macrorhiza:
NW, CaR, SN, SnFrB, SnBr, GB, w DMoj
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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).


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

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).