Mentzelia argillosa

J. Darlington

Ann. Missouri Bot. Gard. 21: 153. 1934.

Common names: Arapien blazingstar
IllustratedEndemicConservation concern
Synonyms: Nuttallia argillosa (J. Darlington) W. A. Weber
Treatment appears in FNA Volume 12. Treatment on page 507. Mentioned on page 499.

Plants perennial, bushlike, with subterranean caudices. Stems multiple, erect, zigzag or straight; branches distal or along entire stem, distal longest or all ± equal, antrorse, straight; hairy. Leaves: blade 15.4–40(–86) × 4–12.2 mm, always some more than 10 mm wide, widest intersinus distance 4–12.2 mm; proximal oblanceolate to spatulate, margins usually entire, rarely dentate, teeth 0(–4), perpendicular to leaf axis, 0.1–1 mm; distal oblanceolate, spatulate, or elliptic, base not clasping, margins usually entire, rarely dentate, teeth 0(–4), perpendicular to leaf axis, 0.3–1.4 mm; abaxial surface with simple grappling-hook, complex grappling-hook, and needlelike trichomes, adaxial surface with simple grappling-hook and needlelike trichomes. Bracts: margins entire. Flowers: petals golden yellow, 8.2–12.2(–15.2) × 2.4–5 mm, apex acute, glabrous abaxially; stamens golden yellow, 5 outermost petaloid, filaments narrowly spatulate, slightly clawed, 5.6–11(–13.5) × 1.4–3 mm, with anthers, second whorl with anthers; anthers usually twisted after dehiscence, epidermis papillate; styles 5.5–9.4 mm. Capsules cup-shaped, 5–8.4 × 3.1–6 mm, base tapering to rounded, not longitudinally ridged. Seeds: coat anticlinal cell walls straight, papillae 3–5 per cell. 2n = 22.


Phenology: Flowering Jun–Aug.
Habitat: Sparsely vegetated steep cliffs or slopes composed of gypsum-rich clayey and gravelly soils.
Elevation: 1600–1900 m.

Discussion

Mentzelia argillosa is endemic to the Arapien Shale formation in Sevier and Sanpete counties.

Selected References

None.

Lower Taxa

None.
... more about "Mentzelia argillosa"
John J. Schenk +  and Larry Hufford +
J. Darlington +
Mentzelia +
Arapien blazingstar +
1600–1900 m. +
Sparsely vegetated steep cliffs or slopes composed of gypsum-rich clayey and gravelly soils. +
Flowering Jun–Aug. +
Ann. Missouri Bot. Gard. +
Illustrated +, Endemic +  and Conservation concern +
Nuttallia argillosa +
Mentzelia argillosa +
Mentzelia sect. Bartonia +
species +