Mentzelia uintahensis

Plants perennial, bushlike, with subterranean caudices or rhizomes. Stems multiple, erect, zigzag or straight; branches distal or along entire stem, distal longest or all ± equal, antrorse, upcurved; hairy. Leaves: blade 17–56 × 5.8–28 mm, widest intersinus distance 1–4.9(–6) mm; proximal oblanceolate to elliptic, margins pinnate to pinnatisect, lobes 4–12, antrorse, 1.9–7.7 mm; distal elliptic to lanceolate, base not clasping, margins pinnate to pinnatisect, lobes 4–12, antrorse, 2.6–13.3 mm; abaxial surface with simple grappling-hook and occasionally complex grappling-hook and needlelike trichomes, adaxial surface with simple grappling-hook and needlelike trichomes. Bracts: margins entire. Flowers: petals golden yellow, 8.5–15.2 × 3.8–7.9 mm, apex acute to rounded, glabrous abaxially; stamens golden yellow, 5 outermost petaloid, filaments broadly spatulate, strongly clawed, 5–10.4 × 2.8–6 mm, with anthers, second whorl with anthers; anthers usually twisted after dehiscence, epidermis smooth; styles 5.8–8.5 mm. Capsules cup-shaped, 4.2–8.8 × 3.6–5.8 mm, base tapering to rounded, not longitudinally ridged. Seeds: coat anticlinal cell walls straight, papillae 4–7 per cell. 2n = 22.

Phenology: Flowering May–Sep.
Habitat: Sparsely vegetated steep talus slopes and roadcuts.
Elevation: 1500–2800 m.

Colo., Utah.

Discussion

Mentzelia uintahensis is known from northwestern Colorado (Rio Blanco, Mesa, and Moffat counties) and northeastern Utah (Carbon, Duchesne, and Uintah counties).

Selected References

None.

Lower Taxa