Mentzelia humilis
Mentzelia lindleyi
gypsum blazingstar
Lindley's blazing star
solitary or multiple, erect, straight;
branches distal or along entire stem, distal longest or all ± equal, antrorse; straight to upcurved; hairy.
blade 25–95 × 5.5–28(–36.2) mm, widest intersinus distance 0.8–9.1 mm;
proximal spatulate to oblanceolate or elliptic, margins pinnate to pinnatisect, lobes 4–16(–20), slightly antrorse or perpendicular to leaf axis, 2.3–11.8(–16.4) mm;
distal elliptic, lanceolate, spatulate, or linear, base not clasping, margins entire or dentate to pinnatisect, teeth or lobes (0–)4–16, slightly antrorse or perpendicular to leaf axis, 2.3–13.8(–16.9) mm;
abaxial surface with simple grappling-hook, needlelike, and sometimes complex grappling-hook trichomes, adaxial surface with simple grappling-hook and needlelike trichomes.
persisting;
petiole present or absent;
blade lanceolate to linear, margins usually deeply lobed, lobes rounded.
petiole absent;
blade ovate to lanceolate, to 17 cm, margins deeply to shallowly lobed.
margins usually entire, rarely pinnate.
green, ovate to lanceolate, 6.1–14.2 × 3.6–5.1 mm, width 1/3–2/3 length, not concealing capsule, margins 3–7-lobed.
petals white, 10.3–13(–28.6) × 1.4–4 mm, apex acute, glabrous abaxially;
stamens white, 5 outermost petaloid, filaments linear to narrowly spatulate, slightly clawed, 8.8–19(–22.3) × 0.7–3.3 mm, without anthers, second whorl without anthers;
anthers straight after dehiscence, epidermis papillate;
styles 6.5–11.3 mm.
sepals 9–19 mm;
petals orange proximally, yellow distally, obovate, 20–40 × (12–)16–33 mm, apex mucronate;
stamens 20+, 12–30 mm, filaments heteromorphic, 5 outermost linear, inner filiform, unlobed;
styles 15–24 mm.
cup-shaped, 5.3–10.2 × (4.2–)5.2–8.6 mm, base rounded, not longitudinally ridged.
clavate, 25–40 × 4–5 mm, axillary curved to 90° at maturity, usually inconspicuously longitudinally ribbed.
coat anticlinal cell walls wavy, papillae 6–12 per cell.
30–40, in 2+ rows distal to mid fruit, tan, dark-mottled or not, irregularly polygonal, surface minutely tessellate under 10x magnification; recurved flap over hilum absent;
seed coat cell outer periclinal wall domed, domes on seed edges less than 1/2 as tall as wide at maturity.
= 36.
Mentzelia humilis
Mentzelia lindleyi
Varieties 2 (2 in the flora).
The basionym of Mentzelia humilis is often cited as M. multiflora var. humilis A. Gray (1852). However, in that publication Gray indicated accepted names in Roman capitals (see ipni.org), whereas the varietal name is in lower case, indicating that he was using it as a descriptive term rather than a scientific name. Valid publication of the basionym thus must be attributed to Urban and Gilg.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Naturally occurring populations of Mentzelia lindleyi are limited primarily to the Coast Ranges of the San Francisco Bay area. However, commercial distribution of seeds has resulted in casual alien populations of M. lindleyi throughout the southwestern United States. See 68. M. crocea for discussion of similarities between these species.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Leaf blade widest intersinus distances 0.8–2.6(–3.3) mm; lobes of proximal leaves 1–2.9 mm wide. | var. humilis |
1. Leaf blade widest intersinus distances 1.6–9.1 mm (always on some leaves greater than 2.6 mm); lobes of proximal leaves (1.1–)2.9–5.1 mm wide. | var. guadalupensis |
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