Mentzelia veatchiana |
Mentzelia densa |
|
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Veatch's blazing star, white-stem blazingstar, white-stem stick-leaf |
Arkansas Canyon stickleaf, royal Gorge blazingstar |
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Habit | Plants candelabra-form, (5–)20–50 cm. | Plants biennial, bushlike. |
Stems | solitary, decumbent to erect, straight; branches along entire stem, distal or proximal longest, antrorse, straight or upcurved, proximal decumbent; hairy. |
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Leaves | blade 32–86 × 5.8–15 mm, widest intersinus distance 1.7–5.2(–7.1) mm; proximal oblanceolate to elliptic, margins dentate to pinnate, teeth or lobes 6–12, perpendicular to leaf axis, 1.2–6.3 mm; distal elliptic to lanceolate, base not clasping, margins dentate to pinnate, teeth or lobes 4–10, perpendicular to leaf axis, 1.8–5.2 mm; abaxial surface with simple grappling-hook, complex grappling-hook, and occasionally needlelike trichomes, largest trichomes without pearly white bases, adaxial surface with simple grappling-hook and needlelike trichomes. |
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Basal leaves | persisting; petiole present or absent; blade linear-lanceolate, margins deeply to shallowly lobed. |
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Cauline leaves | petiole absent; blade ovate-lanceolate to lanceolate, to 17 cm, margins usually deeply lobed to dentate, rarely entire. |
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Bracts | usually green with prominent white base usually conspicuously extending outwards from midvein, rarely green, usually ovate, rarely lanceolate, 3.3–6.2 × 1.5–3.2 mm, width 1/4–7/8 length, not concealing capsule, margins usually 3–7-lobed, rarely entire. |
margins entire or toothed. |
Flowers | sepals 2–5 mm; petals red to orange proximally, orange to yellow distally, 4–7(–10) mm, apex retuse; stamens 20+, 3–7 mm, filaments monomorphic, filiform, unlobed; styles (3–)3.5–6 mm. |
petals golden yellow, 14.2–19.8 × 3.8–6.5 mm, apex acute to rounded, glabrous abaxially; stamens golden yellow, 5 outermost petaloid, filaments narrowly spatulate, slightly clawed, 12–18.1 × 2.7–4.8 mm, with or without anthers, second whorl with anthers; anthers straight after dehiscence, epidermis smooth; styles 8.3–11.1 mm. |
Capsules | clavate, 8–28 × 2–4 mm, axillary curved to 70° at maturity, usually inconspicuously longitudinally ribbed. |
cylindric, 12.2–18 × 4.3–8.3 mm, base tapering, not longitudinally ridged. |
Seeds | 15–35, in 2+ rows distal to mid fruit, tan, dark-mottled, 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 or equal to 1/2 as tall as wide at maturity. |
coat anticlinal cell walls wavy, papillae 7–17 per cell. |
2n | = 54. |
= 20. |
Mentzelia veatchiana |
Mentzelia densa |
|
Phenology | Flowering Mar–Jun. | Flowering Jun–Aug. |
Habitat | Loamy to sandy soils, grasslands, desert scrub, oak-pine woodlands. | Moist canyon walls, lower talus slopes, gravelly and sandy soils. |
Elevation | 200–2500 m. [700–8200 ft.] | 1600–2400 m. [5200–7900 ft.] |
Distribution |
AZ; CA; NV; OR
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CO |
Discussion | Mentzelia veatchiana is the most common and widely distributed hexaploid species in sect. Trachyphytum. It exhibits considerable morphological variation and can be difficult to distinguish from M. montana in northern California. Like the larger-flowered M. pectinata, M. veatchiana has interfertile populations with petal colors ranging from orange to yellow (J. E. Zavortink 1966). When bearing orange petals, M. veatchiana is easily distinguished from other species. Reports of M. veatchiana from Utah are based on specimens treated here as M. montana. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Mentzelia densa is known only from Chaffee and Fremont counties. It is in the Center for Plant Conservation’s National Collection of Endangered Plants. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 543. | FNA vol. 12, p. 522. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | M. albicaulis var. veatchiana | Nuttallia densa |
Name authority | Kellogg: Proc. Calif. Acad. Sci. 2: 99, fig. 28. (1863) | Greene: Pittonia 3: 99. (1896) |
Web links |