Mentzelia decapetala |
Mentzelia nuda |
|
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10-petal western star, evening starflower, gumbo-lily, tenpetal blazingstar |
bractless blazingstar, goodmother, naked blazingstar or western star, stickleaf mentzelia |
|
Habit | Plants biennial or perennial, bushlike, perennials with ground-level caudices. | Plants winter annual, biennial, or perennial, candelabra-form, perennials with ground-level caudices. |
Stems | solitary, erect, straight; branches distal or along entire stem, proximal or distal longest, antrorse, straight to upcurved; hairy. |
solitary (or multiple as wound response), erect, straight; branches distal, distal longest, antrorse, straight; hairy. |
Leaves | blade 72–295 × 14–45 mm, widest intersinus distance 10.1–23.3 mm; proximal oblanceolate or elliptic, margins serrate to pinnate, teeth or lobes 16–26, slightly antrorse, 1–16.5 mm; distal elliptic to lanceolate, base clasping or not, margins serrate to pinnate, teeth or lobes 9–20, slightly antrorse, 5.3–13.7 mm; surfaces with needlelike trichomes. |
blade 37–120 × 5–24.4 mm, widest intersinus distance 4.8–19.6 mm; proximal oblanceolate to elliptic, margins serrate, teeth 14–30, slightly antrorse, 0.6–4.9 mm; distal elliptic to lanceolate, base not clasping, margins serrate, teeth 12–30, slightly antrorse, 0.7–4.7 mm; abaxial surface with simple grappling-hook, complex grappling-hook, and needlelike trichomes, adaxial surface with simple grappling-hook and needlelike trichomes. |
Bracts | margins pinnate. |
margins pinnate. |
Flowers | petals white, 47–75 × 13–22.7 mm, apex acute to attenuate, glabrous abaxially; stamens white to yellow, 5 outermost petaloid, filaments spatulate, strongly clawed, 48–75 × 12–23 mm, without anthers, second whorl with anthers; anthers straight after dehiscence, epidermis smooth; styles 36–53 mm. |
petals white, 22.6–49 × 3.6–10.3 mm, apex acute, glabrous abaxially, stamens white, 5 outermost petaloid, filaments narrowly spatulate, slightly clawed, 20–47 × 3–10.2 mm, without anthers, second whorl without anthers; anthers straight after dehiscence, epidermis smooth; styles 11.5–18.5 mm. |
Capsules | cylindric, 30–43 × 12–17 mm, base tapering, not longitudinally ridged. |
cylindric, 14.5–29 × 6.9–12.3 mm, base tapering or rounded, not longitudinally ridged. |
Seeds | 2.3–4 mm; coat anticlinal cell walls straight, papillae 4–10 per cell. |
coat anticlinal cell walls wavy, papillae 4–8 per cell. |
2n | = 22. |
= 20. |
Mentzelia decapetala |
Mentzelia nuda |
|
Phenology | Flowering Jun–Aug(–Oct). | Flowering Jun–Nov. |
Habitat | Rock outcrops, slopes, dry short-grass prairies, riverbanks, roadsides, loam, limestone, sandy, silty, clayey, and gravelly soils. | Disturbed roadsides, hillsides, stream banks, sandy and rocky soils. |
Elevation | 300–2400 m. (1000–7900 ft.) | 100–2300 m. (300–7500 ft.) |
Distribution |
CO; IA; IL; KS; MN; MT; NE; NM; OK; SD; TX; UT; WY; AB; MB; SK
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CO; KS; MN; MO; NE; NM; OK; SD; TX; WY
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Discussion | Mentzelia decapetala is introduced in Grundy County, Illinois. It appears to be native throughout the rest of its distribution. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Mentzelia nuda is morphologically similar to, and phylogenetically near, M. strictissima (J. J. Schenk 2009), but it can be distinguished from the latter by its much larger flowers and capsules. The two species have adjacent ranges in New Mexico and Texas but do not overlap despite apparently similar habitat requirements. Mentzelia strictissima occurs west and south of M. nuda and abuts against the southernmost portion of the Rocky Mountains. In the northern portion of its range, M. nuda too approaches the foothills of the southern Rocky Mountains and extends eastward into the plains. Mentzelia nuda was collected once in northeastern Illinois in 1901 but apparently did not become established there. Reports of M. nuda from Arizona are based on misidentified material of M. laevicaulis and M. rusbyi. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 504. | FNA vol. 12, p. 504. |
Parent taxa | Loasaceae > Mentzelia > sect. Bartonia | Loasaceae > Mentzelia > sect. Bartonia |
Sibling taxa | ||
Synonyms | Bartonia decapetala | Bartonia nuda, 2: 749., M. stricta |
Name authority | (Pursh) Urban: Ber. Deutsch. Bot. Ges. 10: 263. (1892) | (Pursh) Torrey & A. Gray: Fl. N. Amer. 1: 535. (1840) |
Web links |