Mentzelia laevicaulis
Fl. N. Amer. 1: 535. 1840.
Plants biennial or perennial (in rosette stage), bushlike. Stems solitary, erect, straight; branches distal or along entire stem, proximal or distal longest, antrorse, upcurved; hairy or glabrescent. Leaves: blade 17.4–196 × 6.7–40.4 mm, widest intersinus distance 2.4–24.6 mm; proximal oblanceolate, lanceolate, or elliptic, margins pinnate, lobes 14–44, slightly antrorse, 2.5–8.9 mm; distal lanceolate, base clasping or not, margins pinnate, lobes 6–42, slightly antrorse, 2.1–13.8 mm; abaxial surface with simple grappling-hook, complex grappling-hook, and needlelike trichomes, adaxial surface with needlelike trichomes. Bracts: margins entire or pinnate. Flowers: petals golden yellow, 23.5–70 × 3–17.3 mm, apex acute, glabrous abaxially; stamens golden yellow, 5 outermost not petaloid, filaments linear to narrowly elliptic, not clawed, 17.7–55 × 0.5–2(–2.5) mm, with anthers, second whorl with anthers; anthers straight after dehiscence, epidermis smooth; styles 20.4–57 mm. Capsules cup-shaped to cylindric, 10.6–43 × 6.3–11.1 mm, base tapering or rounded, not longitudinally ridged. Seeds: coat anticlinal cell walls straight, papillae 4–11 per cell. 2n = 22.
Distribution
w North America.
Discussion
Varieties 2 (2 in the flora).
Selected References
None.
Key
| 1 | Petals 43–70 mm; 5 outermost stamens 39–55 mm. | Mentzelia laevicaulis var. laevicaulis |
| 1 | Petals 23.5–40 mm; 5 outermost stamens 17.7–29 mm. | Mentzelia laevicaulis var. parviflora |