Lepidium densiflorum Schrad., Brassicaceae

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Present on Pacific Islands?  yes

Threat only at high elevations?  no

Common name(s): [more details]

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)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Canada Province of British Columbia	Canada (British Columbia)	native	U.S. Dept. Agr., Agr. Res. Serv. (2007)
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. (2007)
United States (west coast) United States (west coast states)	USA (California)	native	U.S. Dept. Agr., Agr. Res. Serv. (2007)
United States (west coast) United States (west coast states)	USA (Washington)	native	U.S. Dept. Agr., Agr. Res. Serv. (2007)

Additional information:  Additional online information about Lepidium densiflorum is available from the Hawaiian Ecosystems at Risk project (HEAR).

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

References:

Hafliger, Toni J./Wolf, Matthias. 1988. Dicot weeds, vol. 1. CIBA-GEIGY Ltd., Basle, Switzerland. 335 pp.

U. S. Government. 2006. Integrated Taxonomic Information System (ITIS) (on-line resource).

U.S. Dept. Agr., Agr. Res. Serv. 2007. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.

Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. 1999. Manual of the flowering plants of Hawaii. Revised edition. Bernice P. Bishop Museum special publication. University of Hawai‘i Press/Bishop Museum Press, Honolulu. 1919 pp. (two volumes).

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.