Mentzelia veatchiana |
Loasaceae |
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Veatch's blazing star, white-stem blazingstar, white-stem stick-leaf |
blazing-star family, loasa family, stickleaf family |
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Habit | Plants candelabra-form, (5–)20–50 cm. | Herbs, subshrubs, shrubs, [or trees], annual, biennial, or perennial, evergreen (leaves withering in age), scabrid, trichomes (1) unbranched and smooth, knobby, notched, or antrorsely or retrorsely barbed, (2) dendritic, and/or (3) stinging. | ||||||||||||||||
Leaves | alternate [opposite], simple; stipules absent; petiole present or absent; blade sometimes lobed, margins entire, serrate, dentate, or crenate; venation pinnate, basal secondary veins commonly present. |
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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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Inflorescences | terminal, cymes, thyrses, racemes, panicles, or flowers solitary. |
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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. |
bisexual, usually radially symmetric, rarely bilaterally symmetric (by bilateral symmetry of corolla, androecium, or gynoecium); perianth and androecium epigynous; hypanthium adnate to ovary proximally and free distally, or completely adnate to ovary; sepals 5, radially symmetric, distinct or connate basally; petals 5, radially or bilaterally symmetric, distinct or connate, sometimes postgenitally coherent; nectary absent or present, distal on ovary; stamens 5–150+, distinct, free or adnate to petal bases, bilaterally or radially symmetric; anthers dehiscing by longitudinal slits; staminodes absent or present, sometimes petaloid and petals appearing to be 6+; pistil 1, 3–7-carpellate, ovary inferior, 1-locular, placentation parietal, subapical, or apical; ovules 1–60+ per locule, anatropous (epitropous); style 1; stigma 1, 2–5(–7)-lobed (lobes usually as many as carpels, except in pseudomonomerous Gronovioideae). |
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Fruits | capsules, dehiscence by apical valves [splitting longitudinally], or cypselae, sepals or sepals and petals persisting. |
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Capsules | clavate, 8–28 × 2–4 mm, axillary curved to 70° at maturity, usually inconspicuously longitudinally ribbed. |
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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. |
1–60+ per fruit. |
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2n | = 54. |
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Mentzelia veatchiana |
Loasaceae |
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Phenology | Flowering Mar–Jun. | |||||||||||||||||
Habitat | Loamy to sandy soils, grasslands, desert scrub, oak-pine woodlands. | |||||||||||||||||
Elevation | 200–2500 m. (700–8200 ft.) | |||||||||||||||||
Distribution |
AZ; CA; NV; OR
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North America; Mexico; Central America; South America; sw Asia (w Arabian Peninsula); Africa; Atlantic Islands (Cape Verde); Pacific Islands |
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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.) |
Genera 20, species ca. 350 (4 genera, 94 species in the flora). Loasaceae are in Cornales and are the sister family of Hydrangeaceae. The two families likely diverged in western North America or Mexico in the Late Cretaceous to Paleocene, 92–58 million years before present (J. J. Schenk and L. Hufford 2010). Most extant species of Loasaceae in western North America date to the Oligocene or more recent times, with the Miocene and later periods being especially rich phases for speciation (Schenk and Hufford; J. Grissom and Hufford, unpubl.). In Loasaceae, Eucnide and Schismocarpus S. F. Blake, a genus restricted to southern Mexico, are the earliest diverging lineages, and the cliff-dwelling habits of these two genera may be plesiomorphic for the family (Hufford et al. 2003). The species-rich genus Mentzelia is well supported as the sister of a clade that consists of the taxonomically depauperate genera Cevallia, Fuertesia Urban, Gronovia Linnaeus, and Petalonyx. Phylogenetic studies support the monophyly of subfamilies Gronovioideae Fenzl and Loasoideae Gilg as conceived by I. Urban and E. Gilg (1900), but their early concept of Mentzelioideae as including both Eucnide and Mentzelia (and also Schismocarpus according to S. F. Blake 1918b; Gilg 1925b) is paraphyletic (Hufford et al.). To enable classification based on monophyly, circumscription of Mentzelioideae should be restricted to Mentzelia. The Mentzelia plus Gronovioideae clade is sister to the more taxon rich subfam. Loasoideae, which is especially prevalent in Andean South America (Hufford et al.). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 12, p. 543. | FNA vol. 12, p. 491. | ||||||||||||||||
Parent taxa | Loasaceae > Mentzelia > sect. Trachyphytum | |||||||||||||||||
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Synonyms | M. albicaulis var. veatchiana | |||||||||||||||||
Name authority | Kellogg: Proc. Calif. Acad. Sci. 2: 99, fig. 28. (1863) | Jussieu | ||||||||||||||||
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