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

white tansy mustard

Habit Annuals; eglandular; sparsely to densely pubescent, sometimes glabrous distally, trichomes dendritic. Biennials; glandular (at least distally); finely pubescent, often canescent, trichomes dendritic, sometimes mixed with simple ones.
Stems

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

erect, unbranched basally, branched distally, 4.5–13 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 1–3 cm;

blade pinnate, oblanceolate to obovate or ovate in outline, 2–10 cm, lateral lobes (2–5 pairs), oblanceolate to lanceolate, (4–12 × 1–5 mm),margins entire or serrate to crenate, (apex obtuse).

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 densely pubescent.

Racemes

considerably elongated in fruit.

considerably elongated in fruit.

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 ascending, greenish to yellowish, oblong, 2–2.9 mm, pubescent, (trichomes dendritic, mixed with glandular papillae);

petals oblanceolate, 1.8–2.6 × 0.5–0.7mm;

median filaments 1.8–2.4 mm;

anthers 0.3–0.5 mm.

Fruiting pedicels

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

divaricate, straight, 13–31 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.

divaricate to erect, linear, slightly torulose, 8–16(–20) × 1–1.3 mm, (abruptly acute at both ends);

valves each with distinct midvein, (sparsely pubescent or glabrescent);

septum not veined;

ovules 48–64 per ovary;

style 0.1–0.2 mm, glabrous.

Seeds

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

biseriate, light brown, ellipsoid, 0.9–1.1 × 0.5–0.6 mm.

2n

= 28.

= 42.

Descurainia sophia

Descurainia adenophora

Phenology Flowering Mar–Jul. Flowering Jun–Aug.
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 forests, sandy grounds, gravelly flats, disturbed areas
Elevation 0-3000 m (0-9800 ft) 1100-2000 m (3600-6600 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
AZ; CA; NM; NV; TX; Mexico (Baja California, Chihuahua, Coahuila)
[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.)

Both L. E. Detling (1939) and R. C. Rollins (1993) treated Descurainia adenophora as a subspecies of D. obtusa, but the differences are so substantial that they should be recognized as distinct species. From the latter, D. adenophora is distinguished by being hexaploid (versus diploid) with densely glandular (versus eglandular) distal parts, longer sepals (2–2.9 versus 1–2 mm) and petals (1.8–2.6 versus 1.2–2 mm), longer fruiting pedicels (13–31 versus 6–15 mm), biseriate (versus uniseriate) seeds, and more ovules (42–64 versus 16–40) per ovary.

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

Source FNA vol. 7, p. 528. FNA vol. 7, p. 520.
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. brevisiliqua, D. californica, D. incana, D. incisa, D. kenheilii, D. longepedicellata, D. nelsonii, D. obtusa, D. paradisa, D. pinnata, D. sophia, D. sophioides, D. torulosa
Synonyms Sisymbrium sophia, Hesperis sophia, Sisymbrium parviflorum, Sophia parviflora Sophia adenophora, D. obtusa subsp. adenophora
Name authority (Linnaeus) Webb ex Prantl: in H. G. A. Engler and K. Prantl, Nat. Pflanzenfam. 55(III,2): 192. (1891) (Wooton & Standley) O. E. Schulz: in H. G. A. Engler, Pflanzenr. 86[IV,105]: 321. (1924)
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