E-Flora BC: Electronic Atlas of the Flora of BC

Mentzelia laevicaulis var. parviflora (Hook.) Torr. & A. Gray (Douglas ex Hook.) C.L. Hitchc.
blazing-star (smoothstem blazingstar)
Loasaceae (Loasa family)

Introduction to Vascular Plants

Photograph

Map

Distribution of Mentzelia laevicaulis var. parviflora
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Species Information

General:
Biennial or short-lived perennial herb from a deep taproot; stems ascending to erect, several, branched, angular, harshly barbed-hairy throughout but nearly glabrous near the bases, 0.3-1 m tall.

Leaves:
Basal leaves linear to shallowly lobed, 10-15 cm long; stem leaves alternate, unstalked, oblong to egg-shaped but less deeply lobed.

Flowers:
Inflorescence of numerous flowers in a compact terminal or axillary cluster; petals 5, lemon yellow, 2.5-8 cm long; calyces 1-2.5 mm long; stamens 2/3 the length of the petals; bracts linear.

Fruits:
Capsules, oblong, 1.5-3.5 cm long; seeds numerous, flattened, winged, greyish-green or brownish.

Notes:
Two, sometimes difficult to separate, varieties are recognized in BC:

1. Petals at least 4-8 cm long; fruits usually over 2 cm long ...................var. laevicaulis

1. Petals 1.5-4 cm long; fruits usually less than 2 cm long...................... var. parviflora (Dougl. ex Hook.) C.L. Hitchc.

Source: The Illustrated Flora of British Columbia

Habitat and Range

Dry slopes in the steppe and lower montane zones; frequent in SC BC; S to MT, UT and CA.

Source: The Illustrated Flora of British Columbia

Status Information

Scientific Name	Origin Status	Provincial Status	BC List (Red Blue List)	COSEWIC
Mentzelia laevicaulis var. laevicaulis	Native	SU	Unknown	Not Listed
Mentzelia laevicaulis var. parviflora	Native	S4	Yellow	Not Listed

BC Ministry of Environment: BC Species and Ecosystems Explorer.

Synonyms

Synonyms and Alternate Names:
Mentzelia brandegeei S. Wats.
Mentzelia douglasii H. St. John

Taxonomic Keys

1. Plants biennials or perennials; seeds flattened...........................M. laevicaulis

1. Plants annuals; seeds not flattened.

2. Basal leaves linear to shallowly lobed; seeds obscurely rough-pimply and apparently smooth 10X magnification; flower bracts mostly egg-shaped to narrowly egg-shaped; inflorescence congested............................M. dispersa

2. Basal leaves oblanceolate, deeply pinnatifid with deeply notched lobes; seeds conspicuously rough-pimply under 10X magnification; flower bracts narrowly to broadly lanceolate; inflorescence not congested.......................M. albicaulis

Source: Illustrated Flora of British Columbia