Mentzelia sect. Bicuspidaria
basal rosette present, not persistent, proximalmost internodes to 10+ mm;
blade without broad basal lobes, margins toothed to pinnate, flat.
stamens all fertile or 1–3(–5) outermost sterile, filaments dorsiventrally flattened, ±monomorphic, linear, or heteromorphic, 1–3(–5) outermost oblanceolate, petaloid, inner linear, distally 2-lobed or unlobed;
ovules (and seeds) oriented perpendicular or ± parallel to long axis of ovary.
cup-shaped, cylindric, or ovoid, straight.
pyriform to ovoid and flattened dorsiventrally, not winged;
seed coat cells polygonal, ± isodiametric, anticlinal walls straight or wavy.
Mentzelia sect. Bicuspidaria
sw United States; nw Mexico
Species 5 (5 in the flora).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. 1–3(–5) outermost stamens staminodial and petaloid (flowers appearing to have 6–8(–10) petals); stamen filaments unlobed; petals lanceolate to oblanceolate, 6–12 mm, apices acute; styles 5–6.5 mm. | M. reflexa |
1. Stamens all fertile, none petaloid (flowers appearing to have 5 petals); stamen filaments all or most distally 2-lobed; petals obovate, 10–65 mm, apices mucronate; styles 6–30 mm. | → 2 |
2. Bracts conspicuous, concealing pedicels, ovaries, and capsules, white with green margins. | M. involucrata |
2. Bracts inconspicuous, not concealing pedicels, ovaries, or capsules, green. | → 3 |
3. Stamen filament lobes 0.6–2.5 mm, anther stalk usually shorter; seeds constricted and grooved at middle. | M. tricuspis |
3. Stamen filament lobes 0.1–0.7 mm, anther stalk equal or longer; seeds widest at middle, not grooved. | → 4 |
4. Petioles absent in cauline leaves, blade base often cordate-clasping; capsules erect; far southwestern Sonoran Desert. | M. hirsutissima |
4. Petioles present in distalmost cauline leaves, blade base not cordate-clasping; proximal capsules nodding, distal erect; central Mojave Desert. | M. tridentata |
