The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

10-petal western star, evening starflower, gumbo-lily, tenpetal blazingstar

blazing-star mentzelia, common blazing-star, giant blazing-star, smooth-stem blazingstar

Habit Plants biennial or perennial, bushlike, perennials with ground-level caudices. Plants biennial or perennial (in rosette stage), bushlike.
Stems

solitary, erect, straight;

branches distal or along entire stem, proximal or distal longest, antrorse, straight to upcurved; hairy.

solitary, erect, straight;

branches distal or along entire stem, proximal or distal longest, antrorse, upcurved; hairy or glabrescent.

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 17.4–196 × 6.7–40.4 mm, widest intersinus distance 2.4–24.6 mm;

proximal oblanceolate, lanceolate, or elliptic, margins pinnate, lobes 14–44, slightly antrorse, 2.5–8.9 mm;

distal lanceolate, base clasping or not, margins pinnate, lobes 6–42, slightly antrorse, 2.1–13.8 mm;

abaxial surface with simple grappling-hook, complex grappling-hook, and needlelike trichomes, adaxial surface with needlelike trichomes.

Bracts

margins pinnate.

margins entire or 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 golden yellow, 23.5–70 × 3–17.3 mm, apex acute, glabrous abaxially;

stamens golden yellow, 5 outermost not petaloid, filaments linear to narrowly elliptic, not clawed, 17.7–55 × 0.5–2(–2.5) mm, with anthers, second whorl with anthers;

anthers straight after dehiscence, epidermis smooth;

styles 20.4–57 mm.

Capsules

cylindric, 30–43 × 12–17 mm, base tapering, not longitudinally ridged.

cup-shaped to cylindric, 10.6–43 × 6.3–11.1 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 straight, papillae 4–11 per cell.

2n

= 22.

= 22.

Mentzelia decapetala

Mentzelia laevicaulis

Phenology Flowering Jun–Aug(–Oct).
Habitat Rock outcrops, slopes, dry short-grass prairies, riverbanks, roadsides, loam, limestone, sandy, silty, clayey, and gravelly soils.
Elevation 300–2400 m. (1000–7900 ft.)
Distribution
from FNA
CO; IA; IL; KS; MN; MT; NE; NM; OK; SD; TX; UT; WY; AB; MB; SK
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; ID; MT; NV; OR; UT; WA; WY; BC
[WildflowerSearch map]
[BONAP county map]
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.)

Varieties 2 (2 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Petals 43–70 mm; 5 outermost stamens 39–55 mm.
var. laevicaulis
1. Petals 23.5–40 mm; 5 outermost stamens 17.7–29 mm.
var. parviflora
Source FNA vol. 12, p. 504. FNA vol. 12, p. 514.
Parent taxa Loasaceae > Mentzelia > sect. Bartonia Loasaceae > Mentzelia > sect. Bartonia
Sibling taxa
M. affinis, M. albescens, M. albicaulis, M. argillicola, M. argillosa, M. aspera, M. asperula, M. candelariae, M. canyonensis, M. chrysantha, M. collomiae, M. congesta, M. conspicua, M. crocea, M. cronquistii, M. densa, M. desertorum, M. dispersa, M. eremophila, M. filifolia, M. floridana, M. flumensevera, M. goodrichii, M. gracilenta, M. hirsutissima, M. holmgreniorum, M. hualapaiensis, M. humilis, M. integra, M. involucrata, M. inyoensis, M. isolata, M. jonesii, M. laciniata, M. laevicaulis, M. lagarosa, M. leucophylla, M. librina, M. lindheimeri, M. lindleyi, M. longiloba, M. marginata, M. memorabilis, M. mexicana, M. micrantha, M. mollis, M. monoensis, M. montana, M. multicaulis, M. multiflora, M. nitens, M. nuda, M. obscura, M. oligosperma, M. oreophila, M. pachyrhiza, M. packardiae, M. paradoxensis, M. pectinata, M. perennis, M. polita, M. procera, M. pterosperma, M. puberula, M. pumila, M. ravenii, M. reflexa, M. reverchonii, M. rhizomata, M. rusbyi, M. saxicola, M. shultziorum, M. sivinskii, M. speciosa, M. springeri, M. strictissima, M. thompsonii, M. tiehmii, M. todiltoensis, M. torreyi, M. tricuspis, M. tridentata, M. uintahensis, M. veatchiana
M. affinis, M. albescens, M. albicaulis, M. argillicola, M. argillosa, M. aspera, M. asperula, M. candelariae, M. canyonensis, M. chrysantha, M. collomiae, M. congesta, M. conspicua, M. crocea, M. cronquistii, M. decapetala, M. densa, M. desertorum, M. dispersa, M. eremophila, M. filifolia, M. floridana, M. flumensevera, M. goodrichii, M. gracilenta, M. hirsutissima, M. holmgreniorum, M. hualapaiensis, M. humilis, M. integra, M. involucrata, M. inyoensis, M. isolata, M. jonesii, M. laciniata, M. lagarosa, M. leucophylla, M. librina, M. lindheimeri, M. lindleyi, M. longiloba, M. marginata, M. memorabilis, M. mexicana, M. micrantha, M. mollis, M. monoensis, M. montana, M. multicaulis, M. multiflora, M. nitens, M. nuda, M. obscura, M. oligosperma, M. oreophila, M. pachyrhiza, M. packardiae, M. paradoxensis, M. pectinata, M. perennis, M. polita, M. procera, M. pterosperma, M. puberula, M. pumila, M. ravenii, M. reflexa, M. reverchonii, M. rhizomata, M. rusbyi, M. saxicola, M. shultziorum, M. sivinskii, M. speciosa, M. springeri, M. strictissima, M. thompsonii, M. tiehmii, M. todiltoensis, M. torreyi, M. tricuspis, M. tridentata, M. uintahensis, M. veatchiana
Subordinate taxa
M. laevicaulis var. laevicaulis, M. laevicaulis var. parviflora
Synonyms Bartonia decapetala Bartonia laevicaulis
Name authority (Pursh) Urban: Ber. Deutsch. Bot. Ges. 10: 263. (1892) (Douglas) Torrey & A. Gray: Fl. N. Amer. 1: 535. (1840)
Web links