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common twinpod, double twinpod, twin bladderpod

Fremont County twinpod, Rocky Mountain or Fremont County twinpod

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.

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).

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.

Racemes

congested, (elongated in fruit, greatly exceeding leaves).

condensed, (subumbellate to slightly more elongated, few-flowered).

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).

Fruiting pedicels

(spreading, straight or slightly curved), 8–12 mm.

(divaricate-ascending, straight to slightly curved), 6–10 mm.

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.

Seeds

flattened.

flattened.

Physaria didymocarpa

Physaria saximontana

Distribution
from FNA
ID; MT; WA; WY; AB; BC
[WildflowerSearch map]
[BONAP county map]
from FNA
MT; WY
[BONAP county map]
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.)

Key
1. Trichomes spreading throughout; basal leaf blade margins dentate.
subsp. lanata
1. Trichomes appressed (except fruits in subsp. didymocarpa); basal leaf blade margins repand to dentate, ± lyrate or, rarely, entire
→ 2
2. Fruits moderately inflated, trichomes spreading.
subsp. didymocarpa
2. Fruits highly inflated (papery), trichomes appressed.
subsp. lyrata
1. Basal leaf blades: margins entire, apices rounded to angled; styles 3-5 mm.
subsp. saximontana
1. Basal leaf blades: margins dentate (teeth broad), apices angled; styles 4-7 mm.
subsp. dentata
Source FNA vol. 7, p. 633. FNA vol. 7, p. 661.
Parent taxa Brassicaceae > tribe Physarieae > Physaria Brassicaceae > tribe Physarieae > Physaria
Sibling taxa
P. acutifolia, P. alpestris, P. alpina, P. angustifolia, P. arctica, P. arenosa, P. argyraea, P. arizonica, P. aurea, P. bellii, P. brassicoides, P. calcicola, P. calderi, P. carinata, P. chambersii, P. cinerea, P. condensata, P. congesta, P. cordiformis, P. curvipes, P. densiflora, P. dornii, P. douglasii, P. eburniflora, P. engelmannii, P. eriocarpa, P. fendleri, P. filiformis, P. floribunda, P. fremontii, P. garrettii, P. geyeri, P. globosa, P. gooddingii, P. gordonii, P. gracilis, P. grahamii, P. hemiphysaria, P. hitchcockii, P. humilis, P. integrifolia, P. intermedia, P. kingii, P. klausii, P. lata, P. lepidota, P. lesicii, P. lindheimeri, P. ludoviciana, P. macrocarpa, P. mcvaughiana, P. montana, P. multiceps, P. navajoensis, P. nelsonii, P. newberryi, P. obcordata, P. obdeltata, P. occidentalis, P. oregona, P. ovalifolia, P. pachyphylla, P. pallida, P. parviflora, P. parvula, P. pendula, P. pinetorum, P. prostrata, P. pruinosa, P. pulvinata, P. purpurea, P. pycnantha, P. rectipes, P. recurvata, P. reediana, P. rollinsii, P. saximontana, P. scrotiformis, P. sessilis, P. spatulata, P. subumbellata, P. tenella, P. thamnophila, P. tumulosa, P. valida, P. vicina, P. vitulifera
P. acutifolia, P. alpestris, P. alpina, P. angustifolia, P. arctica, P. arenosa, P. argyraea, P. arizonica, P. aurea, P. bellii, P. brassicoides, P. calcicola, P. calderi, P. carinata, P. chambersii, P. cinerea, P. condensata, P. congesta, P. cordiformis, P. curvipes, P. densiflora, P. didymocarpa, P. dornii, P. douglasii, P. eburniflora, P. engelmannii, P. eriocarpa, P. fendleri, P. filiformis, P. floribunda, P. fremontii, P. garrettii, P. geyeri, P. globosa, P. gooddingii, P. gordonii, P. gracilis, P. grahamii, P. hemiphysaria, P. hitchcockii, P. humilis, P. integrifolia, P. intermedia, P. kingii, P. klausii, P. lata, P. lepidota, P. lesicii, P. lindheimeri, P. ludoviciana, P. macrocarpa, P. mcvaughiana, P. montana, P. multiceps, P. navajoensis, P. nelsonii, P. newberryi, P. obcordata, P. obdeltata, P. occidentalis, P. oregona, P. ovalifolia, P. pachyphylla, P. pallida, P. parviflora, P. parvula, P. pendula, P. pinetorum, P. prostrata, P. pruinosa, P. pulvinata, P. purpurea, P. pycnantha, P. rectipes, P. recurvata, P. reediana, P. rollinsii, P. scrotiformis, P. sessilis, P. spatulata, P. subumbellata, P. tenella, P. thamnophila, P. tumulosa, P. valida, P. vicina, P. vitulifera
Subordinate taxa
P. didymocarpa subsp. didymocarpa, P. didymocarpa subsp. lanata, P. didymocarpa subsp. lyrata
P. saximontana subsp. dentata, P. saximontana subsp. saximontana
Synonyms Vesicaria didymocarpa, Coulterina didymocarpa
Name authority (Hooker) A. Gray: Gen. Amer. Bor. 1: 162. (1848) Rollins: Contr. Gray Herb. 214: 13. (1984)
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