Physaria chambersii |
Physaria didymocarpa |
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Chambers' bladder-pod, Chambers' physaria, Chambers' twinpod, double bladderpod |
common twinpod, double twinpod, twin bladderpod |
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Habit | Perennials; caudex usually simple, sometimes branched, (thick, cespitose); (silvery) pubescent throughout, trichomes few-rayed, rays furcate, sometimes slightly fused at base, (umbonate, lightly tuberculate to nearly smooth). | 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). | ||||||||
Stems | several from base, erect or decumbent (arising laterally, unbranched), 0.5–1.5 mm. |
several from base, decumbent, (unbranched, leafy for the genus), ca. 1 dm. |
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Basal leaves | (petiole slender); blade obovate to orbicular, 3–6 cm (width 10–20 mm), margins entire or dentate. |
(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). |
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Cauline leaves | blade spatulate, 1–2 cm (width 3–6 mm), margins entire, (apex often acute). |
blade oblanceolate, 1–2 cm (width 4–8 mm), margins entire or with occasional tooth, (apex acute). |
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Racemes | congested. |
congested, (elongated in fruit, greatly exceeding leaves). |
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Flowers | sepals narrowly lanceolate, 5–8(–9) mm; petals narrowly oblanceolate, 9–12 mm, (claw undifferentiated from blade). |
sepals lanceolate to oblong, 6–8 mm, (often keeled); petals spatulate, 10–12 mm. |
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Fruiting pedicels | (divaricate, slightly sigmoid), 8–15 mm. |
(spreading, straight or slightly curved), 8–12 mm. |
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Fruits | (often purplish in age), didymous, subreniform, strongly inflated, 9–18 × 11–21(–30) mm, (papery, base obtuse to slightly cordate, apical sinus V-shaped or convex, open crests rounded); valves (2-keeled on side away from replum, each 3-sided, keels rounded, sides flat or slightly convex, retaining seeds after dehiscence), evenly and densely pubescent; replum oblong, as wide as or wider than fruits, apex obtuse; ovules 4–12 per ovary; style (4–)6–8 mm (exceeding sinus). |
(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. |
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Seeds | flattened. |
flattened. |
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2n | = 8, 10, 16, 24. |
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Physaria chambersii |
Physaria didymocarpa |
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Phenology | Flowering Apr–Jul. | |||||||||
Habitat | Clay hillsides, limestone gravel, dolomite ridges, roadbanks, loose gravel, reddish clay, sagebrush and pinyon-juniper areas | |||||||||
Elevation | 1500-3200 m (4900-10500 ft) | |||||||||
Distribution |
AZ; CA; ID; NV; OR; UT
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ID; MT; WA; WY; AB; BC
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Discussion | Physaria chambersii has been divided into three varieties based on whether the fruit is stipitate (var. canaani) or not, and whether the caudex elongates (var. sobolifera) or not (var. chambersii). In this species and in some others, e.g., P. newberryi, the latter character often depends on substrate and microclimate. Shifting substrates, such as moving sand and talus, often cause caudices to elongate. The species can be confused with 57. P. newberryi. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
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Key |
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Source | FNA vol. 7, p. 631. | FNA vol. 7, p. 633. | ||||||||
Parent taxa | Brassicaceae > tribe Physarieae > Physaria | Brassicaceae > tribe Physarieae > Physaria | ||||||||
Sibling taxa | ||||||||||
Subordinate taxa | ||||||||||
Synonyms | P. chambersii var. canaani, P. chambersii var. sobolifera | Vesicaria didymocarpa, Coulterina didymocarpa | ||||||||
Name authority | Rollins: Rhodora 41: 403, plate 556, figs. 15–18. (1939) | (Hooker) A. Gray: Gen. Amer. Bor. 1: 162. (1848) | ||||||||
Web links |