22. Mentzelia flumensevera (N. H. Holmgren & P. K. Holmgren) J. J. Schenk & L. Hufford, Novon. 19: 118. 2009.
Sevier canyon stickleaf Sevier canyon stickleaf
Mentzelia multicaulis (Osterhout) J. Darlington var. flumensevera N. H. Holmgren & P. K. Holmgren, Syst. Bot. 27: 761, fig. 6E–G. 2002
Plants perennial, bushlike, with subterranean caudices or rhizomes. Stems multiple, erect or decumbent, zigzag; branches along entire stem, all ± equal, antrorse, upcurved; hairy. Leaves: blade 11.2–22 × 5.2–10.2 mm, widest intersinus distance 1.2–2.4 mm; proximal oblanceolate to elliptic, margins pinnate, lobes 4–6, perpendicular to leaf axis, 2.3–4.1 mm; distal elliptic, base not clasping, margins pinnate, lobes 2–4, perpendicular to leaf axis, 1.4–3 mm; abaxial surface with complex grappling-hook and needlelike trichomes, adaxial surface with complex grappling-hook and needlelike trichomes. Bracts: margins entire. Flowers: petals golden yellow, 10–11.2 × 2.9–3.8 mm, apex rounded, glabrous abaxially; stamens golden yellow, 5 outermost petaloid, filaments narrowly spatulate, slightly clawed, 7.3–8.4 × 1.3–1.9 mm, with anthers, second whorl with anthers; anthers straight after dehiscence, epidermis smooth; styles 5.8–8.7 mm. Capsules cup-shaped, 5.6–7.1 × 4–6 mm, base rounded, not longitudinally ridged. Seeds: coat anticlinal cell walls straight, papillae 3–7 per cell.
Flowering Jul–Aug(–Oct). Sparsely vegetated, steep talus slopes composed of gravel and clay, white soils; of conservation concern; 1700–1900 m; Utah.
Mentzelia flumensevera is narrowly distributed across the Piute and Sevier county line.