Mentzelia veatchiana |
Mentzelia isolata |
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Veatch's blazing star, white-stem blazingstar, white-stem stick-leaf |
isolated blazingstar |
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Habit | Plants candelabra-form, (5–)20–50 cm. | Plants annual, without caudices or tubers. |
Stems | erect, to 70 cm. |
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Leaves | petiole to 25 mm (proximal leaves), absent (distal leaves); blade usually lanceolate to hastate, rarely elliptic, basally lobed, sometime with 2 pairs of lobes, or unlobed, to 14 × 4.5 cm, base obliquely obtuse to acute, margins shallowly serrate, apex acute. |
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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. |
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Pedicels | (fruiting) 0.5–0.8 × 1–2 mm (often appearing absent because thick and continuous with capsule). |
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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 orange, 5–7 × 2.3–4 mm, apex cuspidate, hairy on apex and abaxially near apex; stamens 8–12, 4–5.3 mm, filaments heteromorphic, 5 outermost narrowly spatulate, inner filiform; styles 3.8–5.5 mm. |
Capsules | clavate, 8–28 × 2–4 mm, axillary curved to 70° at maturity, usually inconspicuously longitudinally ribbed. |
clavate or funnelform, 12–27 × 3–5 mm, base tapering gradually, capsule and pedicel not well-differentiated. |
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. |
8–12 per capsule, pyriform, without transverse folds. |
2n | = 54. |
= 20. |
Mentzelia veatchiana |
Mentzelia isolata |
|
Phenology | Flowering Mar–Jun. | Flowering Aug–Oct. |
Habitat | Loamy to sandy soils, grasslands, desert scrub, oak-pine woodlands. | Arroyo and canyon bottoms, rocky slopes. |
Elevation | 200–2500 m. [700–8200 ft.] | 1000–1900 m. [3300–6200 ft.] |
Distribution |
AZ; CA; NV; OR
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AZ; Mexico (Sinaloa, Sonora)
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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 isolata intergrades with both M. aspera and M. asperula in southern Arizona. Typically, M. isolata can be distinguished from both M. aspera and M. asperula because its leaf blades are more than two times as long as wide, whereas those of the latter two species are less than two times as long as wide. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 543. | FNA vol. 12, p. 528. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | M. albicaulis var. veatchiana | |
Name authority | Kellogg: Proc. Calif. Acad. Sci. 2: 99, fig. 28. (1863) | Gentry: Brittonia 6: 322. (1948) |
Web links |