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Vascular Plants of California
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Mentzelia obscura


Higher Taxonomy
Family: LoasaceaeView DescriptionDichotomous Key
Common Name: LOASA FAMILY
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


Common Name: BLAZING STAR
Habit: Annual to perennial herb, sometimes subshrub-like; 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-centered, 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 often modified, +- widened, or petal-like, with or without anthers 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, sometimes winged.

eFlora Treatment Author: Joshua M. Brokaw, John J. Schenk, Barry Prigge & David Keil
Reference: Schenk & Hufford 2020 Syst Bot Monogr 110:1--230
Mentzelia obscura H.J. Thomps. & J.E. Roberts
NATIVE
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 rows +- 3 distal to mid-fruit. Seed: +- 1 mm, irregularly rounded distal to mid-fruit, ×-section occasionally triangular with grooves along longitudinal edges proximal to 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.
Jepson eFlora Author: Joshua M. Brokaw, John J. Schenk, Barry Prigge & David Keil
Reference: Schenk & Hufford 2020 Syst Bot Monogr 110:1--230
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)

Previous taxon: Mentzelia nitens
Next taxon: Mentzelia oreophila

Botanical illustration including Mentzelia obscurabotanical illustration including Mentzelia obscura


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Citation for this treatment: Joshua M. Brokaw, John J. Schenk, Barry Prigge & David Keil 2023, Mentzelia obscura, in Jepson Flora Project (eds.) Jepson eFlora, Revision 12, https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=33269, accessed on July 15, 2024.

Citation for the whole project: Jepson Flora Project (eds.) 2024, Jepson eFlora, https://ucjeps.berkeley.edu/eflora/, accessed on July 15, 2024.

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

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Geographic subdivisions for Mentzelia obscura:
D
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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 occurrence).






 

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

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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.
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CCH collections by month Flowering-Fruiting Monthly Counts

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).