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northern tansy-mustard

mountain tansymustard, narrow tansymustard, sticky tansymustard, western tansy-mustard

Habit Annuals or biennials; eglandular or glandular distally; glabrate to moderately pubescent, trichomes dendritic, sometimes mixed with simple ones. Annuals; usually eglandular, rarely glandular; moderately to sparsely pubescent, often glabrous distally, not canescent, trichomes dendritic.
Stems

erect, unbranched or sometimes branched distally, (0.5–)1.5–11(–18) dm.

erect, unbranched or branched proximally, often branched distally, (1.5–)3–6.2(–8.5) dm.

Basal leaves

petiole 0.5–5 cm;

blade pinnate or, sometimes, 2-pinnate, broadly oblanceolate to ovate in outline, 2.5–11.4(–15.2) cm, lateral lobes lanceolate, (to 10 × 4 mm), margins incised.

petiole 0.4–3.5 cm;

blade pinnate, ovate to oblanceolate in outline, 1.5–7 cm, lateral lobes linear or oblong, margins entire or dentate to incised.

Cauline leaves

sessile or shortly petiolate;

blade smaller distally, distal lobes often narrower, surfaces often glabrous or sparsely pubescent.

sessile or shortly petiolate;

blade smaller distally, lobes linear to filiform, margins entire, surfaces usually glabrous, rarely pubescent.

Racemes

elongated or not in fruit, (flowers overtopped by developing fruits).

considerably elongated in fruit.

Flowers

sepals erect, yellowish, oblong, 1.6–2.7 mm, glabrous;

petals narrowly oblanceolate, 2–2.5 × 0.3–0.6 mm;

median filaments 2.5–3.5 mm;

anthers 0.3–0.4 mm.

sepals ascending, yellow, oblong, 1.5–2 mm, glabrous;

petals narrowly oblanceolate, 1.7–2.6 cm × 0.5–1 mm;

median filaments 1.5–2 mm;

anthers 0.3–0.4 mm.

Fruiting pedicels

divaricate to ascending, (often recurved in age), slender, (3–)4–9(–13) mm.

horizontal to divaricate, straight, (8–)10–15(–20) mm.

Fruits

erect to widely spreading, narrowly linear, slightly torulose, (9–)14–30(–34) × 0.6–1.1 mm, (usually terete, rarely slightly flattened, often curved inward);

valves each with obscure midvein;

septum not veined;

ovules 30–62 per ovary;

style obsolete, 0.07–0.3 mm, glabrous.

erect, linear, not torulose, (9–)12–17 × 0.8–1.1 mm, (straight or slightly curved inward);

valves each with obscure midvein;

septum not veined;

ovules 18–32 per ovary;

style 0.1–0.2 mm, glabrous.

Seeds

uniseriate, light brown, narrowly oblong, 1–1.5 × 0.3–0.5 mm.

uniseriate, reddish brown, oblong, 1–1.3 × 0.6–0.7 mm.

2n

= 14.

= 14.

Descurainia sophioides

Descurainia longepedicellata

Phenology Flowering Jun–Sep. Flowering Apr–Jul.
Habitat Open meadows, eroded peat, roadsides, disturbed and waste sites, rocky outcrops, mining dumps, gravelly grounds, stream banks, gullies Sandy plains and banks, dry washes, open hillsides, sagebrush and juniper or pine communities, grasslands
Elevation 0-1000 m (0-3300 ft) 200-2100 m (700-6900 ft)
Distribution
from FNA
AK; BC; MB; NT; NU; YT; Asia (Russian Far East, Siberia)
[BONAP county map]
from FNA
AZ; CO; ID; MT; NV; OR; UT; WA; WY; BC
[WildflowerSearch map]
[BONAP county map]
Discussion

L. E. Detling (1939) treated Descurainia longepedicellata as subsp. filipes of D. pinnata, whereas R. C. Rollins (1993) and N. H. Holmgren (2005b) treated it as a subspecies and variety, respectively, of D. incisa. Molecular data, both nuclear and plastidic (B. E. Goodson 2007), place the three taxa in different, well-supported clades.

R. C. Rollins (1993) and N. H. Holmgren (2005b) reported 2n = 28 and 42 for Descurainia longepedicellata (as D. pinnata var. filipes), but these counts are not vouchered. Rollins indicated that the taxon range extends into California and New Mexico; we have not seen material from those states.

Descurainia longepedicellata resembles D. incisa subsp. paysonii in having long fruiting pedicels and linear leaf lobes with entire margins. The latter is easily distinguished by being canescent (versus not canescent) and having fruits strongly curved inward (versus straight). Because the two taxa are not closely related (B. E. Goodson 2007), the similarities in fruiting pedicels and distalmost leaf segments represent convergence.

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

Source FNA vol. 7, p. 529. FNA vol. 7, p. 524.
Parent taxa Brassicaceae > tribe Descurainieae > Descurainia Brassicaceae > tribe Descurainieae > Descurainia
Sibling taxa
D. adenophora, D. brevisiliqua, D. californica, D. incana, D. incisa, D. kenheilii, D. longepedicellata, D. nelsonii, D. obtusa, D. paradisa, D. pinnata, D. sophia, D. torulosa
D. adenophora, D. brevisiliqua, D. californica, D. incana, D. incisa, D. kenheilii, D. nelsonii, D. obtusa, D. paradisa, D. pinnata, D. sophia, D. sophioides, D. torulosa
Synonyms Sisymbrium sophioides, Hesperis arctica, Sisymbrium arcticum, Sophia sophioides Sisymbrium longepedicellatum, D. brachycarpa var. eglandulosa, D. incisa subsp. filipes, D. incisa var. filipes, D. longepedicellata var. glandulosa, D. pinnata subsp. filipes, D. pinnata var. filipes, D. rydbergii var. eglandulosa, Hesperis longepedicellata, Sisymbrium brachycarpum var. filipes, Sisymbrium incisum var. filipes, Sisymbrium incisum var. xerophilum, Sisymbrium longepedicellatum var. glandulosum, Sophia filipes, Sophia glandifera, Sophia gracilis, Sophia longepedicellata
Name authority (Fischer ex Hooker) O. E. Schulz: in H. G. A. Engler, Pflanzenr. 86[IV,105]: 316. (1924) (E. Fournier) O. E. Schulz: in H. G. A. Engler, Pflanzenr. 86[IV,105]: 324. (1924)
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