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fine-leaf tansy-mustard, fixweed, flixweed, flixweed tansymustard, herb sophia, not much flower, tansy mustard

northern tansy-mustard

Habit Annuals; eglandular; sparsely to densely pubescent, sometimes glabrous distally, trichomes dendritic. Annuals or biennials; eglandular or glandular distally; glabrate to moderately pubescent, trichomes dendritic, sometimes mixed with simple ones.
Stems

erect, unbranched or branched distally, (1–)2–7(–10) dm.

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

Basal leaves

petiole 0.1–2(–3) cm;

blade 2- or 3-pinnate, ovate or oblong to obovate in outline, to 15 cm, lateral lobes linear or oblong, (to 10 × 2 mm), margins entire.

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.

Cauline leaves

sessile or shortly petiolate;

blade smaller distally, distal lobes often narrower, surfaces often glabrous.

sessile or shortly petiolate;

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

Racemes

considerably elongated in fruit.

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

Flowers

sepals erect to ascending, yellowish, oblong, 1.8–2.8 mm, glabrate to sparsely pubescent;

petals narrowly oblanceolate, 2–3 × 0.4–0.6 mm;

median filaments 2–3 mm;

anthers 0.3–0.4 mm.

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.

Fruiting pedicels

divaricate to ascending, straight, (5–)8–15(–20) mm.

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

Fruits

divaricate-ascending to erect, narrowly linear, torulose, (12–)15–27(–30) × 0.5–0.8(–1) mm, (straight or curved upward);

valves each with distinct midvein;

septum with a broad central longitudinal band appearing as 2 or 3 veins;

ovules 20–48 per ovary;

style obsolete, 0.05–0.2 mm, glabrous.

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.

Seeds

uniseriate, reddish brown, oblong, 0.7–1.3 × 0.3–0.6 mm.

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

2n

= 28.

= 14.

Descurainia sophia

Descurainia sophioides

Phenology Flowering Mar–Jul. Flowering Jun–Sep.
Habitat Roadsides, waste places, disturbed sites, railroad embankments, hillsides, mountain slopes, canyon bottoms, stream banks, fields, lawns, pastures, deserts, sagebrush and pinyon-juniper communities Open meadows, eroded peat, roadsides, disturbed and waste sites, rocky outcrops, mining dumps, gravelly grounds, stream banks, gullies
Elevation 0-3000 m (0-9800 ft) 0-1000 m (0-3300 ft)
Distribution
from FNA
AK; AR; AZ; CA; CO; CT; DC; DE; GA; IA; ID; IL; IN; KS; KY; LA; MA; ME; MI; MN; MO; MT; NC; ND; NE; NH; NM; NV; NY; OK; OR; PA; RI; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NF; NS; NT; ON; PE; QC; SK; YT; Eurasia [Introduced in North America; introduced also in Mexico, Central America, South America, South Africa, Australia]
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; BC; MB; NT; NU; YT; Asia (Russian Far East, Siberia)
[BONAP county map]
Discussion

Deviant chromosome counts (e.g., 2n = 12, 14, 20, 38; see R. C. Rollins 1993, N. H. Holmgren 2005b, S. I. Warwick and I. A. Al-Shehbaz 2006) are most certainly erroneous, and the species appears to be exclusively tetraploid based on x = 7.

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

Source FNA vol. 7, p. 528. FNA vol. 7, p. 529.
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. sophioides, D. torulosa
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
Synonyms Sisymbrium sophia, Hesperis sophia, Sisymbrium parviflorum, Sophia parviflora Sisymbrium sophioides, Hesperis arctica, Sisymbrium arcticum, Sophia sophioides
Name authority (Linnaeus) Webb ex Prantl: in H. G. A. Engler and K. Prantl, Nat. Pflanzenfam. 55(III,2): 192. (1891) (Fischer ex Hooker) O. E. Schulz: in H. G. A. Engler, Pflanzenr. 86[IV,105]: 316. (1924)
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