Lewisia |
Lewisia pygmaea |
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bitterroot, lewisia |
alpine lewisia, dwarf lewisia, least, pigmy bitter root, pygmy bitterroot |
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Habit | Herbs, perennial, with enlarged caudices. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Roots | taproots, gradually ramified distally or fusiform to napiform, rarely globose and cormlike, fleshy. |
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Taproots | gradually ramified distally or shortly fusiform, rarely subnapiform. |
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Stems | deciduous, prostrate to erect, scapelike, simple or branched; nodes glabrous. |
± prostrate or suberect, becoming reflexed in fruit, 1–6 cm. |
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Leaves | basal or basal and cauline; basal leaves evergreen or ephemeral, in basal rosettes or tufts (except in L. triphylla); cauline leaves, if present, alternate, opposite, or whorled, ± sessile or gradually or abruptly narrowed basally into broad, clasping petiole; blade fleshy, margins entire, toothed, or crisped, often hyaline near base. |
basal leaves withering at or soon after anthesis, ± sessile or gradually tapered to long petiole, blade linear to linear-oblanceolate, ± flattened, 3–9 cm, margins entire, apex acute to obtuse; cauline leaves absent. |
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Inflorescences | racemose, paniculate, or subumbellate cymes, pedunculate, or with flowers borne singly; bracts persistent, 2(–9) at each flowering node, subequal, margins entire, toothed, or glandular-toothed, herbaceous or scarious. |
2–4(–7)-flowered in racemose cymes or with flowers borne singly; bracts 2, opposite, plus 1 subtending each successive flower if more than 1 flower, linear-oblong, linear-lanceolate, or lanceolate, (2–)4–10 mm, margins glandular-toothed, sometimes eglandular-toothed, apex acute. |
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Flowers | pedicellate or sessile, persistent or disarticulate in fruit; sepals persistent, 2(–9), equal or subequal when paired, margins entire, toothed, or glandular-toothed, herbaceous or scarious; petals (4–)5–10(–19), twisting about and falling away with capsules after anthesis; stamens 1–50, distinct to scarcely connate and/or adnate to petals basally; ovules 1–50; style branched; stigmas 2–8. |
pedicellate, not disarticulate in fruit, 1.5–2 cm diam.; sepals 2, suborbiculate, broadly ovate, or obovate, 2–6 mm, herbaceous at anthesis, margins usually glandular-toothed, sometimes eglandular-toothed or rarely ± entire, apex usually truncate, sometimes rounded, obtuse, subacute, or apiculate; petals 5–9, white, pink, or magenta, sometimes green at base, narrowly oblong, elliptic, or oblanceolate, 4–10 mm; stamens (4–)5–8; stigmas 3–6; pedicel 2–5(–10) mm. |
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Capsules | dehiscence circumscissile near base, splitting from base toward apex. |
4–5 mm. |
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Seeds | 1–50, brown or black, smooth or minutely sculpted, estrophiolate. |
15–24, 1–2 mm, shiny, smooth. |
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x | = 10, 11, 12, 13, 14, 15. |
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2n | = ca. 66. |
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Lewisia |
Lewisia pygmaea |
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Phenology | Flowering late spring–late summer. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Habitat | Open places in short turf or gravelly or rocky substrates | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Elevation | 2300-4200 m [7500-13800 ft] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Distribution |
w North America (including Mexico) |
AZ; CA; CO; ID; MT; NM; NV; OR; UT; WA; WY; AB; BC; YT
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Discussion | Species 16 (16 in the flora). The number and circumscription of species in Lewisia are not widely agreed upon because of morphological variability and intergradation. Natural hybridization is inferred for some plants. In cultivation, the species reputedly freely intercross; most hybrid offspring are sterile. Most species are cultivated by alpine/succulent plant enthusiasts. In the wild, the plants usually occur in small, isolated populations in rocky or gravelly places, especially in canyons or alpine flats. The key to species here has been modified from B. Mathew (1989b). Hybrids, cultivars, and plants in cultivation may not key satisfactorily. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
The circumscription and diagnosis of Lewisia pygmaea is problematic because of morphologic variability, intermediacy, and/or hybridization with L. nevadensis (see L. T. Dempster 1990). In the range of typical forms of L. nevadensis (see discussion under 11. L. nevadensis), one or more forms of L. pygmaea will also occur, but at higher elevations. Segregates of L. pygmaea recognized elsewhere as species include L. glandulosa, which occurs in rocky substrates above 3000 m in the central and southern Sierra Nevada and is characterized by elongate, sinuous taproots (L. T. Dempster 1990); and L. sierrae, which occurs in moist flats above 2400 m in the central Sierra Nevada and includes diminutive plants with irregularly eglandular-toothed (occasionally entire) sepals (B. Mathew 1989b). Dempster postulated that the variable and widely distributed L. pygmaea represents a hybrid species derived from L. nevadensis and L. glandulosa. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 4, p. 476. | FNA vol. 4, p. 483. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Synonyms | Erocallis, Oreobroma | Talinum pygmaeum, Calandrinia grayi, Calandrinia pygmaea, L. exarticulata, L. glandulosa, L. minima, L. pygmaea var. aridorum, L. pygmaea subsp. glandulosa, L. sierrae, Oreobroma aridorum, Oreobroma exarticulatum, Oreobroma glandulosum, Oreobroma grayi, Oreobroma minimum, Oreobroma pygmaeum | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Name authority | Pursh: Fl. Amer. Sept. 2: 360. (1814) | (A. Gray) B. L. Robinson: in A. Gray et al., Syn. Fl. N. Amer. 1: 268. (1897) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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