Mentzelia pectinata
Mentzelia speciosa
San Joaquin blazing star
jeweled blazingstar, showy western star
solitary, erect, straight;
branches distal or along entire stem, distal or proximal longest, antrorse, upcurved; hairy.
blade 43.6–233 × 9.2–34.7 mm, always some longer than 146 mm, widest intersinus distance 5.2–17 mm;
proximal oblanceolate to elliptic, margins serrate to pinnate, teeth or lobes 10–38, slightly antrorse, 1.5–9.4 mm;
distal lanceolate, base not clasping, margins serrate to pinnate, teeth or lobes 8–24, slightly antrorse, 2.9–10.3 mm;
abaxial surface with simple grappling-hook, complex grappling-hook, and needlelike trichomes, adaxial surface with simple grappling-hook and needlelike trichomes.
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.
margins entire.
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 golden yellow, 14.4–28.6 × 3.8–8 mm, apex acute to rounded, glabrous abaxially;
stamens golden yellow, 5 outermost petaloid, filaments narrowly spatulate, slightly clawed, 13–21.3 × 2.9–6.8 mm, without anthers, second whorl with anthers;
anthers straight after dehiscence, epidermis smooth;
styles 8.9–15.2 mm.
clavate, 12–35 × 2–4 mm, axillary curved to 90° at maturity, usually inconspicuously longitudinally ribbed.
cylindric, 13.1–31.1 × 5.7–9.4 mm, base tapering to rounded, not longitudinally ridged.
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.
coat anticlinal cell walls wavy, papillae 4–13 per cell.
= 18.
= 18, 20.
Mentzelia pectinata
Mentzelia speciosa
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.)
Mentzelia sinuata is treated here as a synonym of M. speciosa. The morphological characters previously used to differentiate these taxa are much more variable and overlapping than previous authors have identified, including within material from type populations. Although typical morphological forms of each taxon can be found, intermediate forms are found throughout the putative species’ highly overlapping ranges, often in a single population. The main character used to differentiate the two species has been chromosome number, with M. sinuata having 2n = 18 and M. speciosa having 2n = 20. Until a cytological study is conducted on populations throughout the range, M. speciosa is regarded as a single species that contains two chromosomal lineages.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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