Mentzelia veatchiana |
Mentzelia micrantha |
|
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Veatch's blazing star, white-stem blazingstar, white-stem stick-leaf |
San Luis blazingstar, San Luis or chaparral blazingstar, San Luis stick leaf, small flower stickleaf |
|
Habit | Plants candelabra-form, (5–)20–50 cm. | Plants wandlike or candelabra-form, 10–80 cm. |
Basal leaves | persisting; petiole present or absent; blade linear-lanceolate, margins deeply to shallowly lobed. |
persisting; petiole present or absent; blade lanceolate to linear, margins irregularly deeply lobed to dentate. |
Cauline leaves | petiole absent; blade ovate-lanceolate to lanceolate, to 17 cm, margins usually deeply lobed to dentate, rarely entire. |
petiole present or absent (proximal leaves), absent (distal leaves); blade lanceolate to linear (proximal leaves), orbiculate to lanceolate (distal leaves), to 18 cm, margins irregularly deeply lobed to dentate proximally, dentate or entire distally. |
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. |
green, orbiculate to ovate, 3.4–6.6 × 2.5–5.9 mm, width 3/4 to ± equal length, often concealing capsule, margins sinuate or 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. |
sepals 1–3 mm; petals yellow, 2-5 mm, apex acute; stamens 10–20, 1.5–4 mm, filaments heteromorphic, 5 outermost elliptic, distally 2-lobed, inner filiform, unlobed; styles 2–3(–5) mm. |
Capsules | clavate, 8–28 × 2–4 mm, axillary curved to 70° at maturity, usually inconspicuously longitudinally ribbed. |
cylindric, 6–13 × 1.5–2.5 mm, axillary curved to 20° at maturity, usually inconspicuously, occasionally prominently, longitudinally ribbed. |
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. |
4–10, in 1 row distal to mid fruit, dark brown or tan, dark-mottled, triangular prisms, surface ±smooth to minutely tessellate under 10x magnification; recurved flap over hilum absent; seed coat cell outer periclinal wall flat. |
2n | = 54. |
= 18. |
Mentzelia veatchiana |
Mentzelia micrantha |
|
Phenology | Flowering Mar–Jun. | Flowering Apr–Jun. |
Habitat | Loamy to sandy soils, grasslands, desert scrub, oak-pine woodlands. | Open, often recently-burned or disturbed chaparral or oak woodlands. |
Elevation | 200–2500 m. [700–8200 ft.] | 0–2300 m. [0–7500 ft.] |
Distribution |
AZ; CA; NV; OR
|
CA; Mexico (Baja California)
|
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 micrantha is easily distinguished from other species in sect. Trachyphytum by the presence of two lateral lobes on the filaments of the five outermost stamens. This characteristic is distinct from the filament lobes of some species in sect. Bicuspidaria, which occur on all or most stamens. Phylogenetic studies have found that M. micrantha is not closely related to species in sect. Bicuspidaria (L. Hufford et al. 2003; J. M. Brokaw and Hufford 2010). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 543. | FNA vol. 12, p. 538. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | M. albicaulis var. veatchiana | Bartonia micrantha |
Name authority | Kellogg: Proc. Calif. Acad. Sci. 2: 99, fig. 28. (1863) | (Hooker & Arnott) Torrey & A. Gray: Fl. N. Amer. 1: 535. (1840) |
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