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Mentzelia congesta

Higher Taxonomy
Family: LoasaceaeView DescriptionDichotomous Key

Habit: Annual to subshrub; hairs needle-like, barbed, occasionally stinging. Leaf: alternate [opposite], generally +- pinnate-lobed; stipules 0. Inflorescence: cyme, raceme. Flower: bisexual, radial; sepals generally 5, generally persistent; petals generally 5, free or fused to each other or filament tube; stamens 5--many, filaments thread-like to flat, occasionally fused at base or in clusters; petal-like staminodes occasionally present; pistil 1, ovary inferior, chamber generally 1, placentas generally 3, parietal, style 1. Fruit: capsule or achene. Seed: 1--many.
Genera In Family: 18+ genera, 250 species: especially America (Africa, Pacific).
eFlora Treatment Author: Larry Hufford & Barry Prigge, except as noted
Scientific Editor: Douglas H. Goldman, Bruce G. Baldwin.
Genus: MentzeliaView DescriptionDichotomous Key

Habit: Annual to perennial herb; hairs barbed to needle-like, not stinging; stems pale pink or generally +- white, branched or not. Leaf: linear to ovate, entire to pinnate-lobed; basal in rosettes, generally petioled; cauline generally sessile, +- reduced distally on stem. Inflorescence: generally cyme (or flower 1); bracts green to white, margin green. Flower: sepals lanceolate to deltate, persistent; petals generally 5, free, white to yellow or orange; stamens generally many, +- free, generally unequal, inner filaments generally thread-like; outermost stamens opposite sepal lobes generally modified, +- widened, or petal-like with anther or not; ovary generally cylindric, placentas generally 3, style thread-like, stigma 3-furrowed or -lobed. Fruit: capsule, cup-, barrel-, or urn-shaped to narrowly cylindric, occasionally curved. Seed: generally many, shape variable.
Species In Genus: +- 100 species: western North America, +- tropical America.
eFlora Treatment Author: Joshua M. Brokaw, John J. Schenk & Barry Prigge

Mentzelia congesta Torr. & A. Gray
Habit: Annual 7--40 cm. Stem: erect, glabrous to hairy. Leaf: 1--9 cm, entire to lobed. Inflorescence: dense; outer bract widely ovate, toothed to lobed, +- concealing fruit; inner bract +- fused to ovary, obovate, +- toothed to lobed; lower 3/4 of bracts white-scarious, margin green. Flower: sepals 1--4 mm; petals 3--7(9) mm, obovate, pale yellow to yellow, base orange; stamens +- = style; style 1.5--5 mm. Fruit: generally erect, 5--12 mm, 2--3 mm wide, cylindric. Seed: +- 1 mm, irregular-angular with concave sides, tan, dark-mottled or not; seed coat cells generally domed, < 1/2 tall as wide in age. Chromosomes: 2n=18.
Ecology: Disturbed slopes, pine forest, sagebrush scrub, pinyon/juniper woodland; Elevation: 1200--2700 m. Bioregional Distribution: SNH (e slope), Teh, WTR, SnGb, PR, SNE, DMtns; Distribution Outside California: to Idaho. Flowering Time: May--Jul
Synonyms: Mentzelia congesta var. davidsoniana (Abrams) J.F. Macbr.
eFlora Treatment Author: Joshua M. Brokaw, John J. Schenk & Barry Prigge
Jepson Online Interchange

Previous taxon: Mentzelia albicaulis
Next taxon: Mentzelia crocea

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botanical illustration including Mentzelia congesta


Citation for this treatment: Joshua M. Brokaw, John J. Schenk & Barry Prigge 2016. Mentzelia congesta, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on February 08, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora,, accessed on February 08, 2016.

Mentzelia congesta
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© 2010 James M. Andre
Mentzelia congesta
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© 2011 Neal Kramer
Mentzelia congesta
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© 2010 James M. Andre
Mentzelia congesta
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© 2007 Steve Matson
Mentzelia congesta
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© 2012 Gary A. Monroe
Mentzelia congesta
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© 2010 Steve Matson

More photos of Mentzelia congesta in CalPhotos

Geographic subdivisions for Mentzelia congesta:
SNH (e slope), Teh, WTR, SnGb, PR, SNE, DMtns;
Markers link to CCH specimen records. If the markers are obscured, reload the page [or change window size and reload]. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.
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).

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Data provided by the participants of the Consortium of California Herbaria.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.