Physaria didymocarpa |
Physaria arizonica |
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common twinpod, double twinpod, twin bladderpod |
Arizona bladderpod |
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Habit | Perennials; caudex branched, (cespitose); densely pubescent, trichomes (often stalked, appressed to wavy and spreading), several-rayed, rays furcate or simple, (slightly to strongly umbonate, nearly smooth to strongly tuberculate). | Perennials; caudex branched, (cespitose); densely (silvery gray) pubescent, trichomes (sessile or subsessile), (4-), 6-, or 8-rayed, rays fused at base, furcate or bifurcate, (slightly umbonate, tuberculate throughout). | ||||||||
Stems | several from base, decumbent, (unbranched, leafy for the genus), ca. 1 dm. |
simple or few to several from base, erect, (unbranched, slender), 0.2–1(–1.5) dm. |
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Basal leaves | (forming a strong rosette; long-petiolate); blade obovate, 1.5–4(–8) cm, (base ± abruptly narrowing to petiole), margins usually repand or dentate, rarely entire, (apex usually angular, surfaces silvery). |
(densely tufted, not rosulate, reflexed in age); blade obovate to oblanceolate, 0.7–2(–3) cm, margins usually entire, sometimes repand or shallowly dentate, (apex acute). |
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Cauline leaves | blade oblanceolate, 1–2 cm (width 4–8 mm), margins entire or with occasional tooth, (apex acute). |
similar to basal, becoming narrower distally, somewhat reflexed, (distal) blade linear or narrowly oblanceolate, 0.5–2.5(–5.5) cm. |
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Racemes | congested, (elongated in fruit, greatly exceeding leaves). |
dense, often subcorymbiform. |
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Flowers | sepals lanceolate to oblong, 6–8 mm, (often keeled); petals spatulate, 10–12 mm. |
sepals (green or greenish yellow), ovate or broadly ovate, 3.5–6.5 mm, (lateral pair subsaccate, cucullate, median pair thickened, slightly cucullate apically); petals (spreading), oblanceolate to obovate, 5.5–8(–10) mm, (claw erect). |
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Fruiting pedicels | (spreading, straight or slightly curved), 8–12 mm. |
(erect or divaricate-spreading, straight or slightly curved), (3–)5–10(–15) mm. |
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Fruits | (erect), didymous, inflated, 10–20 × 10–20 mm, (papery or firm, basal sinus shallow to deep, sometimes barely notched, apical sinus deep, narrow, usually closed); valves (retaining seeds after dehiscence), loosely pubescent, trichomes spreading (appearing fuzzy); replum obovate to broadly oblong, not constricted, 3–4 mm, as wide as or wider than fruit, apex obtuse; ovules (4–)8 per ovary; style 7–9 mm. |
(sessile or substipitate), suborbicular to ovoid or ellipsoid, slightly inflated, 4–7 mm; valves pubescent outside, trichomes substipitate, spreading, sometimes sparsely pubescent inside, trichomes sessile, smooth; ovules 4–10(–16) per ovary; style (0.5–)1–2(–4) mm (shorter than fruit). |
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Seeds | flattened. |
flattened. |
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2n | = 10. |
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Physaria didymocarpa |
Physaria arizonica |
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Phenology | Flowering Apr–Jun. | |||||||||
Habitat | Sandy and gravelly soils, limey knolls or limestone chip, often in open stands of sagebrush-pinyon, pinyon-juniper, Gambel oak and sometimes ponderosa pine | |||||||||
Elevation | 1000-2200 m (3300-7200 ft) | |||||||||
Distribution |
ID; MT; WA; WY; AB; BC
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AZ; UT
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Discussion | Subspecies 3 (3 in the flora). The characters used to differentiate Physaria didymocarpa from P. saximontana (especially subsp. dentata) appear to be weak at best: whether there are 4 or 8 ovules per ovary and whether the silicle lacks a basal sinus or one is present. There appears to be intergradation in each of those characters. A traditional circumscription of these species is followed here. Further work is needed at both the species and subspecies level in these taxa. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
The circumscription of Physaria arizonica here is quite broad and includes plants that have densely tufted basal leaves and relatively few or no cauline leaves; plants that are loosely tufted and have several cauline leaves; and plants that have a strongly branched caudex, leafy stems, and sterile shoots (var. andrusensis). Additional study is needed to understand the pattern of variation in this complex species; all of the characters given above vary considerably. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 7, p. 633. | FNA vol. 7, p. 627. | ||||||||
Parent taxa | Brassicaceae > tribe Physarieae > Physaria | Brassicaceae > tribe Physarieae > Physaria | ||||||||
Sibling taxa | ||||||||||
Subordinate taxa | ||||||||||
Synonyms | Vesicaria didymocarpa, Coulterina didymocarpa | Lesquerella arizonica, Lesquerella arizonica var. nudicaulis, P. arizonica var. andrusensis | ||||||||
Name authority | (Hooker) A. Gray: Gen. Amer. Bor. 1: 162. (1848) | (S. Watson) O’Kane & Al-Shehbaz: Novon 12: 321. (2002) | ||||||||
Web links |