Reverchon’s blazingstar Reverchon’s blazingstar

Mentzelia pumila Torrey & A. Gray var. reverchonii Urban & Gilg, Nova Acta Acad. Caes. Leop.-Carol. German. Nat. Cur. 76: 94. 1900; M. hintoniorum B. L. Turner & A. L. Hempel; Nuttallia reverchonii (Urban & Gilg) W. A. Weber

Plants biennial or perennial, candelabra-form, perennials with ground-level caudices. Stems solitary, erect, straight; branches distal, distal longest, antrorse, straight to upcurved; hairy. Leaves: blade 24.2–54 × 6.6–29 mm, widest intersinus distance 5.4–13.5(–22.4) mm; proximal oblanceolate to elliptic, margins dentate to pinnate, teeth or lobes 10–20, perpendicular to leaf axis, 1.1–5 mm; distal lanceolate, base not clasping, margins dentate, teeth 8–14, perpendicular to leaf axis, 0.6–3.8 mm; abaxial surface with simple grappling-hook, complex grappling-hook, and occasionally needlelike trichomes, adaxial surface with simple grappling-hook and needlelike trichomes. Bracts: margins usually toothed, occasionally entire. Flowers: petals golden yellow, (9.6–)11.1–14.1(–22) × 2.5–4.2(–5.5) mm, apex acute to rounded, glabrous abaxially; stamens golden yellow, 5 outermost petaloid, filaments narrowly spatulate, slightly clawed, 9.4–13.4(–20) × 2.2–3.7(–5) mm, without anthers, second whorl with anthers; anthers straight after dehiscence, epidermis smooth; styles 8.7–11.4(–13) mm. Capsules usually cylindric, rarely cup-shaped, 9.4–22 × 6–9.1 mm, length usually more than, occasionally a few slightly less than, 2 times diam., base tapering, not longitudinally ridged. Seeds: coat anticlinal cell walls straight, papillae 5–7 per cell. 2n = 18.

Flowering Apr–Oct. Grasslands on eroded riverbanks, roadsides, roadcuts, sparsely vegetated hillside slopes, sandy, gravelly, clayey, occasionally gypsum soils; 50–600 m; Colo., N.Mex., Okla., Tex.; Mexico (Coahuila, Nuevo León).