Mentzelia veatchiana |
Mentzelia canyonensis |
|
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Veatch's blazing star, white-stem blazingstar, white-stem stick-leaf |
Grand Canyon blazingstar |
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Habit | Plants candelabra-form, (5–)20–50 cm. | Plants perennial, bushlike, with subterranean caudices or rhizomes. |
Stems | multiple, erect or decumbent, zigzag; branches along entire stem, all ± equal, antrorse, upcurved; hairy. |
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Leaves | blade 16–31 × 3.9–9.2 mm, widest intersinus distance 3–-8.3 mm; proximal oblanceolate to elliptic, margins entire or dentate, teeth 0–4(–6), perpendicular to leaf axis, 0.2–1.3 mm; distal oblanceolate to elliptic, base not clasping, margins entire or dentate, teeth 0–4, perpendicular to leaf axis, 0.4–2 mm; abaxial surface with simple grappling-hook (occasionally absent) and complex grappling-hook trichomes, adaxial surface with complex 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. |
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 white, 9–15 × 1.8–2.4 mm, apex rounded to acute, glabrous abaxially; stamens white, 5 outermost petaloid, filaments narrowly spatulate, slightly clawed, 7.1–13 × 0.5–1.4 mm, with anthers, second whorl with anthers; anthers twisted or straight after dehiscence, epidermis papillate; styles 4.8–-7.3 mm. |
Capsules | clavate, 8–28 × 2–4 mm, axillary curved to 70° at maturity, usually inconspicuously longitudinally ribbed. |
cup-shaped, 4.5–8(–13) × 4.5–7 mm, base rounded, 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 straight, papillae usually 6–9 per cell. |
2n | = 54. |
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Mentzelia veatchiana |
Mentzelia canyonensis |
|
Phenology | Flowering Mar–Jun. | Flowering May–Nov. |
Habitat | Loamy to sandy soils, grasslands, desert scrub, oak-pine woodlands. | Loose, rocky soils primarily on steep, degraded slopes, less frequently on stream bottoms, Muav limestones and Bright Angel shales. |
Elevation | 200–2500 m. [700–8200 ft.] | 800–1600 m. [2600–5200 ft.] |
Distribution |
AZ; CA; NV; OR
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AZ |
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 canyonensis is known only from the Grand Canyon and Little Colorado River canyon in Coconino County. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 543. | FNA vol. 12, p. 504. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | M. albicaulis var. veatchiana | |
Name authority | Kellogg: Proc. Calif. Acad. Sci. 2: 99, fig. 28. (1863) | J. J. Schenk: W. C. Hodgson & L. Hufford, Brittonia 65: 410, figs. 1,2. (2013) |
Web links |