Thlaspi arvense L., Brassicaceae

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Present on Pacific Islands?  no

Primarily a threat at high elevations?  no

Risk assessment results:  High risk, score: 19 (Go to the risk assessment)

Common name(s): [more details]

Chinese: xi ming

English: bastard cress, fanweed, field pennycress, Frenchweed, Mithridate mustard, pennycress, stinkweed, wild garlic

Habit:  herb

Description:  "Plants (sometimes glaucous), glabrous throughout. Stems (0.9-) 1.5-5.5 (-8) dm. Basal leaves not rosulate; petiole 0.5-3 cm; blade oblanceolate, spatulate, or obovate, 1-5 cm x 4-23 mm, base attenuate or cuneate, margins entire, repand, or coarsely dentate, apex rounded. Cauline leaves: blade oblong, (0.5-) 1.5-4 (-8) cm x (2-) 5-15 (-25) mm, apex rounded, obtuse, or subacute. Fruiting pedicels straight or slightly upcurved, (5-) 9-13 (-15) mm. Flowers: sepals (1.5-) 2-3 (-3.3) x 1-1.5 mm; petals (2.4-) 3-4.5 (-5) x (0.8-) 1.1-1.7 mm, narrowed to clawlike base (ca. 1 mm), apex obtuse or emarginate; filaments (1-) 1.5-2.2 mm; anthers 0.3-0.5 mm. Fruits obovate or suborbicular, (0.6-) 0.9-2 cm x (5-) 7-20 mm, base obtuse or rounded, apex deeply emarginate, notch ca. 5 mm deep; wings broad throughout, 1-1.5 mm wide basally, 3.5-5 mm wide apically; ovules 6-16 per ovary; style 0.1-0.3 mm. Seeds (1.2-) 1.6-2 (-2.3) x 1.1-1.3 mm, concentrically striate"  (Flora of North America online).

Habitat/ecology:  In the United States:  "Roadsides, fields, waste places, lawns, gardens, railroad tracks, stream banks, bluffs, thickets, slopes, floodplains, woods; 0-2000 m"  (Flora of North America online).  In China (native): "Roadsides, grassy slopes, fields, waste places; 100-5000 m"  (Flora of China online).

Propagation:  Seed

Native range:  Europe and Asia; naturalized elsewhere (GRIN).

Presence:

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Australia Australia (continental)	Australia (continental)	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2011) Victoria Naturalized
Australia Australia (continental)	New South Wales	introduced invasive	National Herbarium of New South Wales (2011) Weed of waste places.
Canada Province of British Columbia	Canada (British Columbia)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2011)
Canada Canada	Canada (country)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2011)
Chile (continental) Chile	Chile (Republic of)	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2011) Naturalized
China China	China (People's Republic of)	native	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2011)
Japan Japan	Japan (country)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011) Hokkaido, Honshu, Kyushu, Shikoku
Japan Ryukyu Islands	Ryukyu Islands	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
North Korea North Korea	North Korea (Democratic People's Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
South Korea South Korea	South Korea (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 447) Arable fields, waste land.
United States (west coast) United States (west coast states)	USA (Oregon)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2011)
United States (west coast) United States (west coast states)	USA (California)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2011)
United States (west coast) United States (west coast states)	USA (Washington)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2011)

Also reported from
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
United States (continental except west coast) United States (other states)	United States (other states)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2011)
United States (continental except west coast) United States (other states)	USA (Florida)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2011)

Additional information:
Identification guide from Virginia Tech.

Additional online information about Thlaspi arvense is available from the Hawaiian Ecosystems at Risk project (HEAR).

Information about Thlaspi arvense as a weed (worldwide references) may be available from the Global Compendium of Weeds (GCW).

Taxonomic information about Thlaspi arvense may be available from the Germplasm Resources Information Network (GRIN).

References:

Flora of North America Editorial Committee, eds. 2011. Flora of North America North of Mexico (online edition).

National Herbarium of New South Wales. 2011. PlantNet: New South Wales Flora online. The Plant Information Network System of the Botanic Gardens Trust Version 2.0. Online resource.

U.S. Dept. Agr., Agr. Res. Serv. 2011. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.

U.S. Dept. Agr., Nat. Res. Cons. Serv. 2011. The PLANTS Database. National Plant Data Center, Baton Rouge, LA 70874-4490 USA.

Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. 1988. Flora of New Zealand, Volume IV: Naturalised pteridophytes, gymnosperms, dicotyledons. Botany Division, DSIR, Christchurch. 1365 pp.

Zhengyi, Wu/Raven, Peter H./Deyuan, Hong. 2011. Flora of China (online resource).