Descurainia sophia |
Descurainia longepedicellata |
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fine-leaf tansy-mustard, fixweed, flixweed, flixweed tansymustard, herb sophia, not much flower, tansy mustard |
mountain tansymustard, narrow tansymustard, sticky tansymustard, western tansy-mustard |
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Habit | Annuals; eglandular; sparsely to densely pubescent, sometimes glabrous distally, trichomes dendritic. | Annuals; usually eglandular, rarely glandular; moderately to sparsely pubescent, often glabrous distally, not canescent, trichomes dendritic. |
Stems | erect, unbranched or branched distally, (1–)2–7(–10) dm. |
erect, unbranched or branched proximally, often branched distally, (1.5–)3–6.2(–8.5) 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 0.4–3.5 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. |
sessile or shortly petiolate; blade smaller distally, lobes linear to filiform, margins entire, surfaces usually glabrous, rarely 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, 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, straight, (5–)8–15(–20) mm. |
horizontal to divaricate, straight, (8–)10–15(–20) 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, 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, reddish brown, oblong, 0.7–1.3 × 0.3–0.6 mm. |
uniseriate, reddish brown, oblong, 1–1.3 × 0.6–0.7 mm. |
2n | = 28. |
= 14. |
Descurainia sophia |
Descurainia longepedicellata |
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Phenology | Flowering Mar–Jul. | Flowering Apr–Jul. |
Habitat | Roadsides, waste places, disturbed sites, railroad embankments, hillsides, mountain slopes, canyon bottoms, stream banks, fields, lawns, pastures, deserts, sagebrush and pinyon-juniper communities | Sandy plains and banks, dry washes, open hillsides, sagebrush and juniper or pine communities, grasslands |
Elevation | 0-3000 m (0-9800 ft) | 200-2100 m (700-6900 ft) |
Distribution |
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]
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AZ; CO; ID; MT; NV; OR; UT; WA; WY; BC
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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.) |
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. 528. | FNA vol. 7, p. 524. |
Parent taxa | Brassicaceae > tribe Descurainieae > Descurainia | Brassicaceae > tribe Descurainieae > Descurainia |
Sibling taxa | ||
Synonyms | Sisymbrium sophia, Hesperis sophia, Sisymbrium parviflorum, Sophia parviflora | 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 | (Linnaeus) Webb ex Prantl: in H. G. A. Engler and K. Prantl, Nat. Pflanzenfam. 55(III,2): 192. (1891) | (E. Fournier) O. E. Schulz: in H. G. A. Engler, Pflanzenr. 86[IV,105]: 324. (1924) |
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