Mentzelia decapetala |
Mentzelia pachyrhiza |
|
---|---|---|
10-petal western star, evening starflower, gumbo-lily, tenpetal blazingstar |
big-root stickleaf, Coahuila blazingstar |
|
Habit | Plants biennial or perennial, bushlike, perennials with ground-level caudices. | Plants perennial, with tubers. |
Stems | solitary, erect, straight; branches distal or along entire stem, proximal or distal longest, antrorse, straight to upcurved; hairy. |
erect, to 50 cm. |
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. |
petiole mostly 3–20 mm, less than 3 mm only on smallest, distalmost leaves; blade ovate to hastate, basally lobed or unlobed, to 4 × 3 cm, base usually acute to obtuse, sometimes attenuate or hastate, margins usually serrate, sometimes crenate, apex acute. |
Bracts | margins pinnate. |
|
Pedicels | (fruiting) (0–)2 × 2 mm. |
|
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 orange, 5–11.5 × 3–5 mm, apex acute to rounded, hairy abaxially on distal 1/2; stamens 15–45, 4–8 mm, filaments usually monomorphic, filiform, rarely heteromorphic, outermost slightly spatulate, inner filiform; style 3–7.5 mm. |
Capsules | cylindric, 30–43 × 12–17 mm, base tapering, not longitudinally ridged. |
subcylindric to clavate, 6–10 × 1.5–2.3 mm, base tapering gradually, capsule and pedicel not well-differentiated, walls thin, brittle. |
Seeds | 2.3–4 mm; coat anticlinal cell walls straight, papillae 4–10 per cell. |
2–3 per capsule, oblong, with transverse folds. |
2n | = 22. |
= 22. |
Mentzelia decapetala |
Mentzelia pachyrhiza |
|
Phenology | Flowering Jun–Aug(–Oct). | Flowering May–Nov. |
Habitat | Rock outcrops, slopes, dry short-grass prairies, riverbanks, roadsides, loam, limestone, sandy, silty, clayey, and gravelly soils. | Steep limestone cliffs, gravelly slopes of gypseous clayey soils, desert scrub and Larrea communities. |
Elevation | 300–2400 m. (1000–7900 ft.) | 900–2000 m. (3000–6600 ft.) |
Distribution |
CO; IA; IL; KS; MN; MT; NE; NM; OK; SD; TX; UT; WY; AB; MB; SK
|
TX; Mexico (Chihuahua, Coahuila, Durango, Nuevo León) |
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 pachyrhiza, native to the Chihuahuan Desert, reaches the flora area only in southern Brewster and Presidio counties. In southwestern Texas and northeastern Chihuahua, where M. pachyrhiza and M. oligosperma have overlapping ranges, H. J. Thompson and A. M. Powell (1981) reported that the former was found at elevations usually below 1100 meters in the Larrea zone, below the elevation of junipers and M. oligosperma. Thompson and Powell allied M. pachyrhiza with M. oligosperma and the South American M. grisebachii Urban & Gilg, now treated as a synonym of M. parvifolia Urban & Gilg ex Kurtz (M. Weigend 2007b). This placement is consistent with phylogenetic studies (J. Grissom and L. Hufford, unpubl.), which show that M. pachyrhiza is the sister species of M. parvifolia; they together are the sister of M. oligosperma and the Mexican M. pattersonii B. L. Turner. I. M. Johnston’s (1940) assertion that the large tuber of M. pachyrhiza is unique in sect. Mentzelia is incorrect. Tubers, often carrot-shaped, are common among the perennial species of the section. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 504. | FNA vol. 12, p. 529. |
Parent taxa | Loasaceae > Mentzelia > sect. Bartonia | Loasaceae > Mentzelia > sect. Mentzelia |
Sibling taxa | ||
Synonyms | Bartonia decapetala | |
Name authority | (Pursh) Urban: Ber. Deutsch. Bot. Ges. 10: 263. (1892) | I. M. Johnston: J. Arnold Arbor. 21: 71. (1940) |
Web links |