Mentzelia pectinata
Mentzelia asperula
San Joaquin blazing star
mountain stickleaf, Organ Mountain blazingstar
erect, to 25 cm.
petiole to 12 mm (proximal leaves), absent (distal leaves);
blade usually ovate to hastate, or smallest distal elliptic or lanceolate, basally lobed or unlobed, to 4.5 × 3.5 cm, base cuneate or obtuse to truncate, margins serrate, apex acute.
persisting;
petiole present or absent;
blade lanceolate to linear, margins deeply to shallowly lobed.
petiole absent;
blade ovate to linear, to 12 cm, margins deeply lobed to dentate.
green, ovate to lanceolate, 6.6–12.8 × 1.9–6.8 mm, width 1/5–2/3 length, not concealing capsule, margins 3–7-lobed.
(fruiting) 1–3 × 2 mm.
sepals 3–13 mm;
petals red to orange proximally, orange to yellow distally, 8–22 mm, apex mucronate, rounded, or retuse;
stamens 20+, 4–11 mm, filaments monomorphic, filiform, unlobed;
styles 5–13 mm.
petals orange, 5–8 × 3–5 mm, apex cuspidate, hairy abaxially at apex;
stamens 10–20, 5–8 mm, filaments monomorphic, filiform;
style 3–5 mm.
clavate, 12–35 × 2–4 mm, axillary curved to 90° at maturity, usually inconspicuously longitudinally ribbed.
subcylindric to clavate, 12–25 × 3–5 mm, base tapering gradually, capsule and pedicel not well-differentiated.
20–40, in 2+ rows distal to mid fruit, tan, dark-mottled or not, usually irregularly polygonal, occasionally triangular prisms proximal to mid fruit, surface tuberculate under 10x magnification; recurved flap over hilum absent;
seed coat cell outer periclinal wall domed, domes on seed edges more than 1/2 as tall as wide at maturity.
(7–)8–10(–12) per capsule, pyriform, without transverse folds.
= 18.
= 20, 40.
Mentzelia pectinata
Mentzelia asperula
Mentzelia pectinata occurs in Kern, San Luis Obispo, Santa Barbara, and Tulare counties, around the southern rim of the San Joaquin Valley, extending into the Inner Coast Ranges and the southern foothills of the Sierra Nevada. Petal color varies from orange to yellow, and fully fertile artificial hybrids have been obtained between populations representing the extreme phenotypes (J. E. Zavortink 1966). Phylogenetic studies suggest that M. pectinata and M. congesta have hybridized to form several allopolyploid species (J. M. Brokaw and L. Hufford 2010b) despite their current allopatric distributions.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Populations consistent with the form and geographic region of the type specimen of Mentzelia asperula (collected in southwestern New Mexico) have been recovered in two clades of sect. Mentzelia. In one clade, M. asperula is closely related to M. isolata; in the second clade, it is closely related to M. gypsophila B. L. Turner of northern Mexico (J. Grissom 2014). The polyphyly of M. asperula likely represents convergence on rapid developmental times and small, self-fertilizing flowers. In southeastern Arizona, M. asperula can be difficult to distinguish from M. isolata; see the discussion of the latter for more information.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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