Physaria didymocarpa |
Physaria saximontana |
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common twinpod, double twinpod, twin bladderpod |
Fremont County twinpod, Rocky Mountain or Fremont County twinpod |
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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 usually simple; (silvery) pubescent throughout, trichome rays furcate. | ||||||||||||
Stems | several from base, decumbent, (unbranched, leafy for the genus), ca. 1 dm. |
several from base, prostrate to decumbent, 0.3–1 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). |
(rosulate; petiole winged); blade orbicular to broadly obovate, 1.5–3 cm, margins entire or with broad, obscure toothlike angles each side at apex, (apex obtuse, surfaces densely pubescent, trichomes appressed). |
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Cauline leaves | blade oblanceolate, 1–2 cm (width 4–8 mm), margins entire or with occasional tooth, (apex acute). |
blade broadly spatulate to linear-oblanceolate, 1–1.5 cm, margins entire. |
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Racemes | congested, (elongated in fruit, greatly exceeding leaves). |
condensed, (subumbellate to slightly more elongated, few-flowered). |
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Flowers | sepals lanceolate to oblong, 6–8 mm, (often keeled); petals spatulate, 10–12 mm. |
sepals (yellowish, often with some purple), narrowly lanceolate, 5–6 mm; petals spatulate, 7.3–9.2 mm, (not clawed). |
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Fruiting pedicels | (spreading, straight or slightly curved), 8–12 mm. |
(divaricate-ascending, straight to slightly curved), 6–10 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. |
didymous, irregular, suborbicular, deeply bilobed, inflated in age, 10–12 × 12–15 mm, (papery, basal sinus absent or obsolete, apical sinus deep); valves (retaining seeds after dehiscence), densely pubescent, trichomes spreading, (ovaries and immature fruit downy); replum narrowly ovate to broadly oblong, not narrowed at middle, as wide as or wider than fruit, apex acute to obtuse; ovules 4 per ovary; style 3–7 mm. |
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Seeds | flattened. |
flattened. |
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Physaria didymocarpa |
Physaria saximontana |
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Distribution |
ID; MT; WA; WY; AB; BC
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MT; WY |
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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.) |
Subspecies 2 (2 in the flora). Physaria saximontana (especially subsp. dentata) is morphologically similar to 22. P. didymocarpa. (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. 661. | ||||||||||||
Parent taxa | Brassicaceae > tribe Physarieae > Physaria | Brassicaceae > tribe Physarieae > Physaria | ||||||||||||
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Subordinate taxa | ||||||||||||||
Synonyms | Vesicaria didymocarpa, Coulterina didymocarpa | |||||||||||||
Name authority | (Hooker) A. Gray: Gen. Amer. Bor. 1: 162. (1848) | Rollins: Contr. Gray Herb. 214: 13. (1984) | ||||||||||||
Web links |