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bitterroot, lewisia

alpine lewisia, dwarf lewisia, least, pigmy bitter root, pygmy bitterroot

Habit Herbs, perennial, with enlarged caudices.
Roots

taproots, gradually ramified distally or fusiform to napiform, rarely globose and cormlike, fleshy.

Taproots

gradually ramified distally or shortly fusiform, rarely subnapiform.

Stems

deciduous, prostrate to erect, scapelike, simple or branched;

nodes glabrous.

± prostrate or suberect, becoming reflexed in fruit, 1–6 cm.

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.

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.

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.

Capsules

dehiscence circumscissile near base, splitting from base toward apex.

4–5 mm.

Seeds

1–50, brown or black, smooth or minutely sculpted, estrophiolate.

15–24, 1–2 mm, shiny, smooth.

x

= 10, 11, 12, 13, 14, 15.

2n

= ca. 66.

Lewisia

Lewisia pygmaea

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
from USDA
w North America (including Mexico)
[BONAP county map]
from FNA
AZ; CA; CO; ID; MT; NM; NV; OR; UT; WA; WY; AB; BC; YT
[WildflowerSearch map]
[BONAP county map]
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.)

Key
1. Roots globose, cormlike; basal leaves usually senescent before anthesis; cauline leaves in single pair or whorl of 3(-5)
L. triphylla
1. Roots elongate, gradually ramified distally, or fusiform to napiform; basal leaves evergreen or senescent at or immediately following anthesis; cauline leaves in more than 1 opposite pair or alternate, or absent
→ 2
2. Basal leaves evergreen
→ 3
2. Basal leaves senescing at or soon after anthesis
→ 6
3. Basal leaf blades linear to narrowly oblanceolate, margins entire
→ 4
3. Basal leaf blades oblanceolate, spatulate, obovate, orbiculate, or very rarely nearly linear, margins entire or toothed
→ 5
4. Leaves ± terete
L. leeana
4. Leaves flattened or adaxial surface grooved
L. columbiana
5. Petals 5-9 mm, white to pale pink with darker veins; cymes loosely paniculate
L. cantelovii
5. Petals (8-)10-20 mm, usually pink-purple with pale and darker stripes, less often white, cream with pink-orange stripes, ± orange, or yellow; cymes densely paniculate to subumbellate
L. cotyledon
6. Flowers sessile; bract and sepal pairs decussate and appearing to form 4-merous calyx
→ 7
6. Flowers pedicellate; bracts and sepals not resembling 4-merous calyx
→ 8
7. Sepal margins toothed, sometimes glandular; petals 10-15 mm
L. kelloggii
7. Sepal margins entire, not glandular; petals 12-26 mm
L. brachycalyx
8. Flowers disarticulate in fruit; sepals 2-9, scarious at anthesis, margins entire to somewhat erose, not toothed
→ 9
8. Flowers not disarticulate in fruit; sepals 2, herbaceous at anthesis, margins entire, toothed, or glandular-toothed
→ 11
9. Sepals (4-)6-9; petals 10-19; proximalmost bracts in whorl of 4-7(-8)
L. rediviva
9. Sepals 2-4; petals 5-9; proximal bracts in 1 pair or whorl of 3-4
→ 10
10. Sepals 2; petals 5-8; bracts ovate to lanceolate; flowers borne singly; s Sierra Nevada, California
L. disepala
10. Sepals 3-4; petals 7-9; bracts oblong to oblong-ovate; inflorescences 2-3-flowered or flowers borne singly; Nye County, Nevada
L. maguirei
11. Cauline leaves opposite, in 1-3 pairs, not markedly smaller than basal leaves
L. oppositifolia
11. Cauline leaves absent or alternate, markedly smaller than basal leaves
→ 12
12. Basal leaf blades oblanceolate, spatulate, or obovate; inflorescences paniculate or subumbellate cymes, 3-100-flowered
→ 13
12. Basal leaf blades linear to linear-oblanceolate; inflorescences 2-7-flowered racemose cymes or flowers borne singly
→ 14
13. Inflorescences 3-7-branched paniculate cymes, 20-100-flowered; petals 6-7, pale pink with yellow-green bases; stamens 4-5; Mari- posa County, California
L. congdonii
13. Inflorescences 1-3-branched subumbellate cymes, 3-11-flowered; petals 7-10, magenta or carmine with whitish bases; stamens 10-13; n Coast Ranges, California
L. stebbinsii
14. Flowers 2.5-4 cm diam.; Eldorado County, Nevada, and Placer County, California
L. longipetala
14. Flowers 0.5-2 cm diam.; more widely distributed
→ 15
15. Sepal margins mostly entire, sometimes obscurely or irregularly toothed, not glan- dular, apex acute to subacute; taproot napiform to shortly fusiform
L. nevadensis
15. Sepal margins regularly toothed, usually glandular-toothed (rarely ± entire), apex truncate or sometimes rounded, obtuse, subacute, or apiculate; taproot gradually ramified distally or shortly fusiform, rarely subnapiform
L. pygmaea
Source FNA vol. 4, p. 476. Authors: Mark A. Hershkovitz, Sean B. Hogan. FNA vol. 4, p. 483.
Parent taxa Portulacaceae Portulacaceae > Lewisia
Sibling taxa
L. brachycalyx, L. cantelovii, L. columbiana, L. congdonii, L. cotyledon, L. disepala, L. kelloggii, L. leeana, L. longipetala, L. maguirei, L. nevadensis, L. oppositifolia, L. rediviva, L. stebbinsii, L. triphylla
Subordinate taxa
L. brachycalyx, L. cantelovii, L. columbiana, L. congdonii, L. cotyledon, L. disepala, L. kelloggii, L. leeana, L. longipetala, L. maguirei, L. nevadensis, L. oppositifolia, L. pygmaea, L. rediviva, L. stebbinsii, L. triphylla
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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