Jepson eFlora: Taxon page
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Mentzelia obscura

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 obscura H.J. Thomps. & J.E. Roberts
Habit: Annual 8--45 cm. Stem: erect to decumbent, glabrous to hairy. Leaf: 1--22 cm; entire to lobed. Inflorescence: bracts generally ovate, entire, green. Flower: sepals 2--6 mm; petals 3--7(8) mm, ovate to occasionally obovate, yellow, base yellow to orange; stamens 2--7 mm; style 2--6 mm. Fruit: curved < 250°, 11--31 mm, 1.5--3 mm wide, obconic. Seed: +- 1 mm, irregularly rounded above mid-fruit, ×-section occasionally triangular with grooves along longitudinal edges below mid-fruit, tan, not or sparsely dark-mottled; seed coat cells domed, < 1/2 tall as wide in age. Chromosomes: 2n=36.
Ecology: Sandy to rocky washes, slopes, roadsides, creosote-bush scrub, blackbush scrub, Joshua-tree woodland; Elevation: 200--1616 m. Bioregional Distribution: D; Distribution Outside California: to Utah, Arizona, northern Mexico. Flowering Time: Feb--Mar Note: Intergrades with Mentzelia desertorum, Mentzelia albicaulis.
eFlora Treatment Author: Joshua M. Brokaw, John J. Schenk & Barry Prigge
Jepson Online Interchange

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Next taxon: Mentzelia oreophila

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botanical illustration including Mentzelia obscura


Citation for this treatment: Joshua M. Brokaw, John J. Schenk & Barry Prigge 2016. Mentzelia obscura, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on October 28, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora,, accessed on October 28, 2016.

Mentzelia obscura
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© 2012 James M. Andre
Mentzelia obscura
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© 2012 James M. Andre
Mentzelia obscura
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© 2014 Neal Kramer
Mentzelia obscura
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© 2014 Neal Kramer
Mentzelia obscura
click for enlargement
© 2014 Neal Kramer

More photos of Mentzelia obscura in CalPhotos

Geographic subdivisions for Mentzelia obscura:
Markers link to CCH specimen records. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues. Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
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.
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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.