Mentzelia mexicana

Plants biennial, bushlike or candelabra-form. Stems solitary, erect, straight; branches distal or along entire stem, distal or proximal longest, antrorse, upcurved; hairy. Leaves: blade 24–82 × 11.7–29.1 mm, widest intersinus distance 3.4–19 mm; proximal oblanceolate or elliptic, margins dentate, serrate, or pinnate, teeth or lobes 6–16, slightly antrorse or perpendicular to leaf axis, 1.4–5.1 mm; distal elliptic to lanceolate, base usually not clasping, sometimes a few clasping, margins dentate, serrate, or pinnate, teeth or lobes 6–12, slightly antrorse or perpendicular to leaf axis, 2.5–6.7 mm; abaxial surface with simple grappling-hook, complex grappling-hook, and usually needlelike trichomes, adaxial surface with simple grappling-hook and needlelike trichomes. Bracts: margins entire. Flowers: petals golden yellow, 10.2–15.3 (–17) × 2.5–6.2 mm, apex rounded, glabrous abaxially; stamens golden yellow, 5 outermost petaloid, filaments narrowly spatulate, slightly clawed, 9.9–14.4 (–16.7) × 2–4.8 mm, without anthers, second whorl with anthers; anthers straight after dehiscence, epidermis smooth; styles 4.5–10.9 mm. Capsules cupshaped, 7.1–12.8 × 5.6–8.4 mm, length to 2 times diam., base rounded, not longitudinally ridged. Seeds: coat anticlinal cell-walls straight, papillae 8–12 per cell. 2n = 18.

Phenology: Flowering Mar–Oct.
Habitat: Arroyos, knolls, steep slopes, gypsum and limestone clay and shale.
Elevation: 700–1500 m.

Tex., Mexico (Chihuahua), Mexico (Coahuila), Mexico (Nuevo León), Mexico (Zacatecas)

Discussion

In the flora area, Mentzelia mexicana occurs in Brewster, Hudspeth, and Presidio counties.

Selected References

None.

Lower Taxa