Mentzelia torreyi
Mentzelia holmgreniorum
Torrey's blazing star
Holmgrens' blazingstar
5–25 cm.
solitary, erect, straight;
branches distal or along entire stem, distal or proximal longest, antrorse, upcurved; hairy.
petiole absent;
blade ovate or obovate, to 45 × 35 mm, intersinus distance 2–4 mm.
blade 42–89 × 11–31.9 mm, widest intersinus distance 2.3–3.6 mm;
proximal oblanceolate to elliptic, margins pinnatisect, lobes 14–20, strongly antrorse, 4.9–14.4 mm;
distal lanceolate, base not clasping, margins pinnatisect, lobes 12–18, strongly antrorse, 4.2–12.4 mm;
abaxial surface with simple grappling-hook, complex grappling-hook, and needlelike trichomes, adaxial surface with simple grappling-hook and needlelike trichomes.
margins pinnate.
0(–1.5) mm.
petals yellow to orange, narrowly spatulate to obovate, 4.5–17 × 1.2–5 mm, apex rounded;
stamens 25–45, 7–21 mm;
styles 7–18 mm.
petals golden yellow, 13.5–18.8 × 5.2–6.6 mm, apex rounded, glabrous abaxially;
stamens golden yellow, 5 outermost petaloid, filaments narrowly spatulate, slightly clawed, 11.1–16 × 2.7–5 mm, without anthers, second whorl with anthers;
anthers straight after dehiscence, epidermis smooth;
styles 8.4–10.6 mm.
3–7 × 3–4.5 mm.
cylindric, 13.1–14.6 × 5.8–6.9 mm, base tapering, not longitudinally ridged.
3–9 per capsule, edges prominently to inconspicuously ridged.
coat anticlinal cell walls sinuous, papillae 26–51 per cell.
= 28.
= 20.
Mentzelia torreyi
Mentzelia holmgreniorum
Varieties 2 (2 in flora).
In the phylogenetic study by L. Hufford et al. (2003), Mentzelia torreyi was recovered as the sister to the rest of the genus.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Mentzelia holmgreniorum is known from Apache, Coconino, and Navajo counties, Arizona, and Catron County, New Mexico. It is allopatric from the species most similar to it (M. filifolia, M. laciniata, and M. lagarosa), occurring south and west of all three; it differs from all these species in having upcurved rather than straight branches, and from M. filifolia and M. laciniata in having both simple grappling-hook and needlelike trichomes (versus only needlelike trichomes) on its adaxial leaf surfaces. In addition, M. holmgreniorum differs from M. filifolia in having leaf blades with greater intersinus distances (2.3–3.6 mm versus 1–2.4 mm) and wider lobes (1.6–2.5 mm versus 0.8–1.4 mm), from M. laciniata in having pinnate bracts (versus usually entire, rarely pinnate), and from M. lagarosa in having leaf blade lobes that are strongly antrorsely oriented (versus slightly antrorsely or perpendicular to the leaf axis) and flowers with larger petals (13.5–18.8 × 5.2–6.6 mm versus 8.3–13 × 2.2–5.4 mm) and longer outermost stamens (11.1–16 mm versus 6.5–10.7 mm).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Petals 8–17 mm, yellow; longest stamens to 1 mm longer than petals. | var. torreyi |
1. Petals 4.5–8 mm, orangish yellow, orange, or burnt orange; longest stamens usually much more than 1 mm longer than petals. | var. acerosa |
CA
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
