Physaria didymocarpa |
Physaria reediana |
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common twinpod, double twinpod, twin bladderpod |
alpine bladderpod, reed's twinpod, Rollins' 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 simple or branched, (covered with persistent leaf bases, loosely cespitose); densely pubescent, trichomes (appressed to ascending, plant appearing shaggy, always appressed on fruits), 4- or 5-rayed, rays furcate or bifurcate, (tuberculate throughout). | ||||||||
Stems | several from base, decumbent, (unbranched, leafy for the genus), ca. 1 dm. |
few to several from base, ± erect, (arising laterally, also from within basal leaves), 0.2–0.4 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). |
(erect); blade linear-oblanceolate, 1.2–2.8 cm, (base gradually narrowed to petiole), margins entire. |
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Cauline leaves | blade oblanceolate, 1–2 cm (width 4–8 mm), margins entire or with occasional tooth, (apex acute). |
blade linear, similar to basal. |
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Racemes | congested, (elongated in fruit, greatly exceeding leaves). |
dense, (often subumbellate, not or barely exceeding basal leaves). |
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Flowers | sepals lanceolate to oblong, 6–8 mm, (often keeled); petals spatulate, 10–12 mm. |
sepals (pale green-yellow), oblong to elliptic, 4–5 mm, (median pair usually thickened apically, cucullate); petals lingulate, 6–9 mm. |
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Fruiting pedicels | (spreading, straight or slightly curved), 8–12 mm. |
(ascending, curved), 3–5.5 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. |
lanceolate in outline, compressed (latiseptate) on margins and at apex, 4–5 mm; valves pubescent, trichomes closely appressed; ovules 8–12 per ovary; style 3.5–4.5 mm (equaling or exceeding length of fruit, curved proximal to stigma). |
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Seeds | flattened. |
plump, (oblong). |
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Physaria didymocarpa |
Physaria reediana |
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Phenology | Flowering May–Jul. | |||||||||
Habitat | Open areas of grasslands on calcareous soils | |||||||||
Elevation | 1200-1900 m (3900-6200 ft) | |||||||||
Distribution |
ID; MT; WA; WY; AB; BC
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CO; NE; 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.) |
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Key |
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Source | FNA vol. 7, p. 633. | FNA vol. 7, p. 660. | ||||||||
Parent taxa | Brassicaceae > tribe Physarieae > Physaria | Brassicaceae > tribe Physarieae > Physaria | ||||||||
Sibling taxa | ||||||||||
Subordinate taxa | ||||||||||
Synonyms | Vesicaria didymocarpa, Coulterina didymocarpa | Vesicaria alpina, Alyssum alpinum, Lesquerella alpina, Lesquerella alpina var. laevis, Lesquerella condensata var. laevis | ||||||||
Name authority | (Hooker) A. Gray: Gen. Amer. Bor. 1: 162. (1848) | O’Kane & Al-Shehbaz: Novon 12: 327. (2002) | ||||||||
Web links |