Mentzelia aspera
Mentzelia holmgreniorum
dal-pega, rough stickleaf, tropical blazingstar, tropical stickleaf
Holmgrens' blazingstar
erect to decumbent, to 30 cm.
solitary, erect, straight;
branches distal or along entire stem, distal or proximal longest, antrorse, upcurved; hairy.
petiole 10–65 mm;
blade hastate to ovate, usually basally lobed, sometimes unlobed, to 18 × 10 cm, base cuneate to truncate, margins serrate to crenate, apex acute.
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.
(fruiting) 1–3 × 2 mm (often appearing absent because thick and continuous with capsule).
petals orange or yellow, 5–15 × 3–7 mm, apex cuspidate, hairy abaxially at apex;
stamens 20–30, 5 mm, filaments heteromorphic, 5 outermost narrowly spatulate, inner filiform;
style 5 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.
subcylindric to clavate, 9–30 × 3–3.5 mm, base tapering gradually, capsule and pedicel not well-differentiated.
cylindric, 13.1–14.6 × 5.8–6.9 mm, base tapering, not longitudinally ridged.
5–9 per capsule, pyriform to oblong, without transverse folds.
coat anticlinal cell walls sinuous, papillae 26–51 per cell.
= 20.
= 20.
Mentzelia aspera
Mentzelia holmgreniorum
Mentzelia aspera is uncommon in southern Arizona. It is the most widespread species of the genus and is regarded as weedy by some authors (H. J. Thompson and A. M. Powell 1981).
(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.)
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