Lepidium densiflorum Schrad., Brassicaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

Chinese: mi hua du xing cai

English: apetalous peppergrass, common pepperweed, greenflower pepperweed, miner's pepperwort, miners cress, miners pepperweed, peppergrass, pepperweed, prairie peppergrass, prairie pepperweed

French: lépidie densiflore, passerage à fleurs denses

Habit:  herb

Description:  "Annual or sometimes biennial herbs; stems ascending to erect, 2-5 dm long, usually branched above base, usually pubescent, the hairs spreading, occasionally glabrate.  Basal leaves 4-6 (-10) cm long, deeply serrate; cauline leaves somewhat reduced, 1-3 cm long, serrate to subentire.  Flowers in dense racemes 5-10 cm long, somewhat narrowed toward apex; sepals ca. 0.5 mm long, caducous, margins white; petals filiform, less than ca. 0.4 mm long, or absent; stamens 2 (4).  Silicles broadly obovate to suborbicular, usually 2-2.5 mm long, the apical notch narrow, prominent, the margins clearly exceeding the style.  Seeds 1-1.3 mm long"  (Wagner et al., 1999; p. 407).

Habitat/ecology:  In Hawai‘i, "known only from disturbed sites on northern, leeward Hawai‘i [island]"  (Wagner et al., 1999; p. 407).

Propagation:  Seed

Native range:  Central and eastern United States (Wagner et al., 1999; p. 407).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 407) Voucher cited: Bryan s.n. (BISH)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Oppenheimer, Hank L. (2004) (p. 10) West Maui. Voucher cited: Oppenheimer & R. Bartlett H110204 (BISH)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
British Columbia (province of Canada) Province of British Columbia	Canada (British Columbia)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
China China	China (People's Republic of)	introduced invasive	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013) Seashores, sandy places, roadsides; near sea level to 3800 m. Hebei, Heilongjiang, Jilin, Liaoning, Shandong, Yunnan
Japan Japan	Japan	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 183)
Mexico Mexico	Mexico (United Mexican States)		Hafliger, Toni J./Wolf, Matthias (1988) (p. 180)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 430) "Dry roadsides, stony waste land".
United States (west coast) United States (west coast states)	USA (Oregon)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (west coast) United States (west coast states)	USA (California)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (west coast) United States (west coast states)	USA (Washington)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)

Control:  If you know of control methods for Lepidium densiflorum, please let us know.