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Oregon twin-pod

Snake River or creeping twinpod, Snake River twinpod

Habit Perennials; caudex simple, (cespitose); (silvery) pubescent throughout, trichomes (stalked), few-rayed, rays furcate or imperfectly so, (tuberculate throughout). Perennials; caudex usually branched, (rhizomelike, cespitose); densely (silvery) pubescent, trichomes (often stalked, appressed), several-rayed, rays furcate or bifurcate, (umbonate, strongly tuberculate throughout).
Stems

several from base, erect or somewhat decumbent, (unbranched), 1–3.5 dm.

several from base, ± erect, exceeding basal rosette by ± 0.5 dm.

Basal leaves

(petiole slender, usually incised or with broad teeth along petiole);

blade obovate, 4–6 cm, margins entire.

(forming a strong rosette; long-petiolate);

blade oblanceolate to ovate or orbicular, (1.5–)2–4(–8) cm, (base usually abruptly tapering to petiole), margins entire.

Cauline leaves

blade oblanceolate or broader, 1.5–2.5 cm, margins entire or sparsely dentate, (apex acute).

blade oblanceolate, 1–2 cm, margin entire, (apex acute).

Racemes

somewhat loose, (5–15 cm).

congested, (greatly exceeding leaves).

Flowers

sepals oblong, 5–7 mm;

petals (lemon yellow), spatulate, 9–12 mm.

sepals often keeled, 6–8 mm;

petals spatulate, 8–10 mm.

Fruiting pedicels

(spreading or ascending, curved, fruits not pendent), 10–20 mm.

(spreading, straight or slightly curved), 7–11 mm.

Fruits

didymous, obreniform, moderately inflated, angustispetate, (8–)10–12(–15) × 10–14(–16) mm, (papery, not keeled, basal sinus absent, apical sinus broad and open);

valves (retaining seeds after dehiscence, rounded or irregular), loosely pubescent, trichomes spreading;

replum broadly lanceolate, as wide as or wider than fruit, apex acute;

ovules 8 per ovary;

style 1–2 mm.

didymous, highly inflated, 8–22 × 10–25 mm, (papery, basal and apical sinuses deep);

valves (retaining seeds after dehiscence), densely pubescent, trichomes appressed;

replum linear to oblong, as wide as or wider than fruit;

ovules 8 per ovary;

style 7–9 mm.

Seeds

flattened.

flattened.

2n

= 8.

= 16.

Physaria oregona

Physaria integrifolia

Phenology Flowering Apr–Jun. Flowering (May-)Jun–Jul(-Aug).
Habitat Gravelly banks, stream shores, rocky slopes, dry hillsides, serpentine soils Calcareous hills and slopes, shale-limestone cliffs, bare steep slopes, red clay banks, shale
Elevation 900-1900 m (3000-6200 ft) 1900-2700 m (6200-8900 ft)
Distribution
from FNA
ID; OR; WA
[WildflowerSearch map]
[BONAP county map]
from FNA
ID; MT; WY
[BONAP county map]
Discussion

Physaria integrifolia has traditionally been recognized as a variety of P. didymocarpa, but it is morphologically and ecologically quite distinctive. Variety monticola (no combination has been made at subspecific rank) is not recognized here; it is considered another example, in the genus, of caudices elongating in response to shifting substrates.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 7, p. 655. FNA vol. 7, p. 644.
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. 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. 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. 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
Synonyms Coulterina oregona, Lesquerella oregona P. didymocarpa var. integrifolia, P. integrifolia var. monticola
Name authority S. Watson: Proc. Amer. Acad. Arts 17: 363. (1882) (Rollins) Lichvar: Madroño 31: 203. (1984)
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