Mentzelia veatchiana |
Mentzelia thompsonii |
|
---|---|---|
Veatch's blazing star, white-stem blazingstar, white-stem stick-leaf |
Thompson's stickleaf |
|
Habit | Plants candelabra-form, (5–)20–50 cm. | Plants wandlike or candelabra-form, 5–20 cm. |
Basal leaves | persisting; petiole present or absent; blade linear-lanceolate, margins deeply to shallowly lobed. |
not persisting. |
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 ovate to linear (proximal leaves), ovate to lanceolate (distal leaves), to 6 cm, margins entire. |
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, elliptic to oblanceolate, 3.3–6.2 × 1.5–3.2 mm, width 1/4–7/8 length, not concealing capsule, 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. |
sepals 1–3 mm; petals yellow, 2–4 mm, apex retuse to rounded; stamens 10–30, 2–3.5 mm, filaments monomorphic, filiform, unlobed; styles 1.5–3 mm. |
Capsules | clavate, 8–28 × 2–4 mm, axillary curved to 70° at maturity, usually inconspicuously longitudinally ribbed. |
cylindric or clavate, 5–16(–20) × 2–4 mm, axillary curved to 45° at maturity, often 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. |
10–25, in 2+ rows distal to mid fruit, tan, dark-mottled, irregularly polygonal, surface smooth to minutely tessellate under 10x magnification; recurved flap over hilum absent; seed coat cell outer periclinal wall domed, domes on seed edges less than 1/2 as tall as wide at maturity. |
2n | = 54. |
= 18. |
Mentzelia veatchiana |
Mentzelia thompsonii |
|
Phenology | Flowering Mar–Jun. | Flowering Apr–Jun. |
Habitat | Loamy to sandy soils, grasslands, desert scrub, oak-pine woodlands. | Barren clay to silt slopes, usually on Mancos Shale barrens. |
Elevation | 200–2500 m. [700–8200 ft.] | 1300–2000 m. [4300–6600 ft.] |
Distribution |
AZ; CA; NV; OR
|
CO; NM; UT |
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 thompsonii was originally described as Acrolasia humilis, which has caused some confusion with M. humilis (A. Gray) J. Darlington of sect. Bartonia (J. J. Schenk 2009). Subsequently, M. thompsonii was incorrectly treated as a synonym of M. humilis by J. T. Kartesz and C. A. Meacham (1999), leading to lack of recognition of this easily distinguished species in several plant databases and herbaria. Mentzelia thompsonii is distributed predominantly along the Colorado-Utah border south to the Four Corners region. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 543. | FNA vol. 12, p. 542. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | M. albicaulis var. veatchiana | Acrolasia humilis, A. thompsonii |
Name authority | Kellogg: Proc. Calif. Acad. Sci. 2: 99, fig. 28. (1863) | Glad: Madroño 23: 289, figs. 2A,B. (1976) |
Web links |