Physaria didymocarpa |
Physaria gracilis |
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common twinpod, double twinpod, twin bladderpod |
spreading 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). | Annuals or biennials; (delicate, wiry); with a fine taproot; pubescent, trichomes (sessile or subsessile), 4–7-rayed, rays distinct, usually furcate, occasionally bifurcate, (smooth to somewhat tuberculate). | ||||||||||||
Stems | several from base, decumbent, (unbranched, leafy for the genus), ca. 1 dm. |
simple to several from base, erect, often outer decumbent, (unbranched or branched distally), 1–7 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). |
blade oblanceolate to elliptic, 1.5–8(–11.5) cm, margins lyrate-pinnatifid to dentate or repand, (abaxial surface densely pubescent, adaxial sparsely pubescent). |
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Cauline leaves | blade oblanceolate, 1–2 cm (width 4–8 mm), margins entire or with occasional tooth, (apex acute). |
(proximal petiolate, distal sessile); blade oblanceolate to oblong, 1–7 cm, margins dentate to repand. |
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Racemes | congested, (elongated in fruit, greatly exceeding leaves). |
loose, (elongated). |
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Flowers | sepals lanceolate to oblong, 6–8 mm, (often keeled); petals spatulate, 10–12 mm. |
sepals elliptic or broadly ovate, 3–6.5(–8) mm, (median pair slightly thickened apically, cucullate); petals (yellow to orange), broadly obovate, 6–11 mm, (narrowing gradually to short claw). |
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Fruiting pedicels | (spreading, straight or slightly curved), 8–12 mm. |
(usually divaricate-spreading, sometimes horizontal or shallowly recurved, straight or slightly curved), (7–)10–20(–25) mm, (slender or stout). |
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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. |
(stipitate or subsessile, gynophore 1–2 mm), globose, subglobose, obpyriform, or obovoid, not or slightly inflated, 3–9 mm; valves (not retaining seeds after dehiscence), glabrous throughout or sparsely pubescent inside; replum as wide as or wider than fruit; ovules 8–20(–28) per ovary; style 2–4.5 mm. |
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Seeds | flattened. |
slightly flattened. |
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Physaria didymocarpa |
Physaria gracilis |
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Distribution |
ID; MT; WA; WY; AB; BC
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AL; IA; IL; KS; LA; MO; MS; OK; TN; TX
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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). (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. 641. | ||||||||||||
Parent taxa | Brassicaceae > tribe Physarieae > Physaria | Brassicaceae > tribe Physarieae > Physaria | ||||||||||||
Sibling taxa | ||||||||||||||
Subordinate taxa | ||||||||||||||
Synonyms | Vesicaria didymocarpa, Coulterina didymocarpa | Vesicaria gracilis, Alyssum gracile, Lesquerella gracilis | ||||||||||||
Name authority | (Hooker) A. Gray: Gen. Amer. Bor. 1: 162. (1848) | (Hooker) O’Kane & Al-Shehbaz: Novon 12: 323. (2002) | ||||||||||||
Web links |