Mentzelia memorabilis N. H. Holmgren & P. K. Holmgren, Syst. Bot. 27: 753, fig. 4. 2002. (as memorabalis).
[C E]

Nine-eleven blazingstar, 9/11 blazingstar, September 11 stickleaf

Plants perennial, bushlike, with subterranean caudices. Stems multiple, erect, straight; branches distal, distal longest, antrorse, straight; hairy. Leaves: blade 17–36.6 × 1.1–4.8 mm, widest intersinus distance 1.1–4.8 mm; proximal linear to oblanceolate, margins entire; distal linear, base not clasping, margins entire; 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, 7.4–11 × 2.6–3.4 mm, apex rounded, glabrous abaxially; stamens golden yellow, 5 outermost petaloid, filaments narrowly spatulate, slightly clawed, 5.5–9.1 × 1.4–2.7 mm, with anthers, second whorl with anthers; anthers twisted or straight after dehiscence, epidermis smooth; styles 4.8–8 mm. Capsules cup-shaped, 3.6–5.3 × 3.1–4.2 mm, base rounded, not longitudinally ridged. Seeds: coat anticlinal cell walls straight, papillae 6–10 per cell.

Flowering Jun–Sep. Barren gypsum-clay outcrops and hilltops; of conservation concern; 1400–1700 m; Ariz.

Mentzelia memorabilis occurs on the Uinkaret Plateau in Mohave County.  Since its publication, it has also been found near the UT-AZ border in Washington County, Utah on gypsiferous soils with heavy soil crusts where it grows with two other rare Arizona strip endemics, Phacelia hughesii and Tetradymia canescens var. thorneae.