Mentzelia speciosa

Osterhout

Bull. Torrey Bot. Club 28: 689. 1901.

Common names: Jeweled blazingstar showy western star
Endemic
Basionym: Mentzelia aurea Osterhout Bull. Torrey Bot. Club 28: 644. 1901
Synonyms: M. sinuata (Rydberg) R. J. Hill Nuttallia sinuata (Rydberg) Daniels N. speciosa (Osterhout) Greene Touterea sinuata Rydberg
Treatment appears in FNA Volume 12. Treatment on page 522. Mentioned on page 502.

Plants biennial, bushlike or candelabra-form. Stems solitary, erect, straight; branches distal or along entire stem, distal or proximal longest, antrorse, upcurved; hairy. Leaves: 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. Bracts: margins entire. Flowers: 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. Capsules cylindric, 13.1–31.1 × 5.7–9.4 mm, base tapering to rounded, not longitudinally ridged. Seeds: coat anticlinal cell-walls wavy, papillae 4–13 per cell. 2n = 18, 20.


Phenology: Flowering Jun–Sep.
Habitat: Dry hillside slopes, roadcuts, roadsides, reddish, rocky soils.
Elevation: 1500–3000 m.

Discussion

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.

Selected References

None.

Lower Taxa

None.
... more about "Mentzelia speciosa"
petaloid +  and heteromorphic +
1.3 cm13 mm <br />0.013 m <br /> (2.13 cm21.3 mm <br />0.0213 m <br />) +
clawed +  and spatulate +
0.29 cm2.9 mm <br />0.0029 m <br /> (0.68 cm6.8 mm <br />0.0068 m <br />) +
Acute (?) +  and Rounded (?) +
John J. Schenk +  and Larry Hufford +
Osterhout +
ridged +, tapering +  and rounded +
Mentzelia aurea +
4.36 cm43.6 mm <br />0.0436 m <br /> (23.3 cm233 mm <br />0.233 m <br />) +
unlobed;lobed;orbiculate;obovate;unlobed;lobed;orbiculate;obovate;unlobed;lobed;orbiculate;obovate;oblanceolate;spatulate;linear;lanceolate;elliptic;ovate;cordate;deltate;hastate +
0.52 cm5.2 mm <br />0.0052 m <br /> (1.7 cm17 mm <br />0.017 m <br />) +
widest;9.2mm;34.7mm +
upcurved +  and antrorse +
distal +  and along entire stem +
1.31 cm13.1 mm <br />0.0131 m <br /> (3.11 cm31.1 mm <br />0.0311 m <br />) +
cylindric +
0.57 cm5.7 mm <br />0.0057 m <br /> (0.94 cm9.4 mm <br />0.0094 m <br />) +
Jeweled blazingstar +  and showy western star +
Colo. +  and Wyo. +
1500–3000 m. +
curved +  and straight +
s--shaped +, clavate +, urceolate +, ovoid +, cylindric +, subcylindric +, lingulate +  and cup-shaped +
simple +  and complex +
Dry hillside slopes, roadcuts, roadsides, reddish, rocky soils. +
free +  and adnate +
unlobed +  and filiform +
cauline +  and basal +
entire +, serrate +  and pinnate +
apical +, subapical +  and inferior +
perpendicular +  and oriented +
not elongating +
inconspicuous +
connate +  and distinct +
1.44 cm14.4 mm <br />0.0144 m <br /> (2.86 cm28.6 mm <br />0.0286 m <br />) +
spreading +  and erect +
hairy +  and glabrous +
Obovate (?) +, Oblanceolate (?) +, Elliptic (?) +, Ovate (?) +  and Spatulate (?) +
0.38 cm3.8 mm <br />0.0038 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
Flowering Jun–Sep. +
0 cm0 mm <br />0 m <br /> (1 cm10 mm <br />0.01 m <br />) +
Bull. Torrey Bot. Club +
flattened +  and ovoid +
persistent +
lanceolate +  and narrowly ovate +
golden yellow +
adnate +, free +  and distinct +
included +  and exserted +
straight +
papillate +
3-lobed +  and lingulate +
0.89 cm8.9 mm <br />0.0089 m <br /> (1.52 cm15.2 mm <br />0.0152 m <br />) +
M. sinuata +, Nuttallia sinuata +, N. speciosa +  and Touterea sinuata +
Mentzelia speciosa +
Mentzelia sect. Bartonia +
species +
0.29 cm2.9 mm <br />0.0029 m <br /> (1.03 cm10.3 mm <br />0.0103 m <br />) +
dendritic +  and unbranched +
sinuous +  and straight +
plant +, candelabra-form +  and bushlike +