Jepson eFlora: Taxon page
Vascular Plants of California
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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.

eFlora Treatment Author: Joshua M. Brokaw, John J. Schenk & Barry Prigge
Reference: Darlington 1934 Ann Missouri Bot Gard 21:103--226
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.
Jepson eFlora Author: Joshua M. Brokaw, John J. Schenk & Barry Prigge
Reference: Darlington 1934 Ann Missouri Bot Gard 21:103--226
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)

Previous taxon: Mentzelia albicaulis
Next taxon: Mentzelia crocea

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Botanical illustration including Mentzelia congesta

botanical illustration including Mentzelia congesta


Citation for this treatment: Joshua M. Brokaw, John J. Schenk & Barry Prigge 2012, Mentzelia congesta, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on November 29, 2022.

Citation for the whole project: Jepson Flora Project (eds.) 2022, Jepson eFlora,, accessed on November 29, 2022.

Mentzelia congesta
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© 2012 Gary A. Monroe
Mentzelia congesta
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© 2019 Neal Kramer
Mentzelia congesta
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© 2010 James M. Andre
Mentzelia congesta
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© 2016 Keir Morse
Mentzelia congesta
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© 2016 Keir Morse
Mentzelia congesta
click for enlargement
© 2012 Neal Kramer

More photos of Mentzelia congesta in CalPhotos

Geographic subdivisions for Mentzelia congesta:
SNH (e slope), Teh, WTR, SnGb, PR, SNE, DMtns
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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.
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.

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).