Salsola tragus L., Chenopodiaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  See risk assessment for Salsola kali.

Common name(s): [more details]

English: Russian cactus, Russian thistle, Russian tumbleweed, spineless saltwort, tumbleweed

French: soude épineuse, soude roulante

Habit:  herb

Description:  "Annual herbs; stems 3-10 dm long, intricately many-branched, forming a round, bushy clump, with age breaking off and becoming a tumbleweed, glabrous or sometimes sparsely hirsute.  Leaves linear, terete when fresh, somewhat flattened when dry, 3-5 cm long, upper leaves usually only 0.5-0.8 cm long, apex spine-tipped.  Calyx with enlarged membranous wings in fruit, 3-6 mm wide when well-developed, those of lowermost flowers often merely carinate.  Seed black, shiny, 1.5-2 mm in diameter"  (Wagner et al., 1999; pp. 540-541).

Description from the Flora of North America

See also Salsola kali.

Habitat/ecology:  In Hawai‘i, "sparingly naturalized along roadsides and in other disturbed areas on Hawai‘i (Big) Island"  (Wagner et al., 1999; p. 541), "in industrial area hard pan and nearby scrub" on Moloka‘i (Starr, Starr & Loope, 2006; p. 34), a roadside weed on Maui (Oppenheimer & Bartlett, 2002; pp. 5-6), on former sugarcane fields and in scrub vegetation on O‘ahu (Herbst et al., 2004; p. 5).

Propagation:  Seed.  The dry, ball-shaped plant breaks off at ground level when mature and is rolled by the wind, spreading seeds as it goes.

Native range:  Eurasia and north Africa (GRIN).

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) (pp. 540-541) Misidentified as Salsola kali. Spreading only slowly. Voucher cited: Kawasaki 4 (BISH)
State of Hawaii Hawaiian Islands	Kaho‘olawe Island	introduced invasive	Herbst, Derral R./Wagner, Warren L. (1999) (p. 19) Vouchers cited: Aschmann s.n. (BISH 634258), Aschmann s.n. (BISH 634259), Aschmann s.n. (BISH 634257)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Oppenheimer, Hank L./Bartlett, Randal T. (2002) (pp. 5-6) Voucher cited: Oppenheimer H50014 (BISH)
State of Hawaii Hawaiian Islands	Moloka‘i Island	introduced invasive	Starr, Forest/Starr, Kim/Loope, Lloyd L. (2006) (p. 34) Voucher cited: Starr & Starr 050516-3 (BISH)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Herbst, Derral R./Staples, George W./Imada, Clyde T. (2004) (p. 5) Voucher cited: W. Char & C. Morden s.n. (BISH 695053)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
China China	China (People's Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2009) Salsola kali L>

Control: 

Physical:  "Cattle will graze the plant, and fence lines bar the movement of detached plants.  These may be the reasons Russian thistle has not spread faster than it has"  (Motooka et al., 2003).

Chemical: "It is very sensitive to hormone-type dicot killers"  (Motooka et al., 2003).

Additional information:
Information from the book "Weeds of Hawaii‘s Pastures and Natural Areas; An Identification and Management Guide" (Motooka et al., 2003). (PDF format).
Report (PDF format) from US Geological Survey, Biological Resources Division, Haleakala Field Station, Hawaii "Plants of Hawaii".
Information from the Global Invasive Species Database.

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

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

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

References:

Herbst, Derral R./Staples, George W./Imada, Clyde T. 2004. New Hawaiian plant records for 2002-2003. In: Evenhuis, Neal L. and Eldredge, Lucius G., eds. Records of the Hawaii Biological Survey for 2003. Part 1: Articles. Bishop Museum Occasional Papers. 78:3-12.

Herbst, Derral R./Wagner, Warren L. 1999. Contributions to the flora of Hawai‘i. VII. In: Evenhuis, Neal L. and Eldredge, Lucius G., eds. Records of the Hawaii Biological Survey for 1998. Part 1: Articles. Bishop Museum Occasional Papers. 58:12-36.

Motooka, Philip/Castro, Luisa/Nelson, Duane/Nagai, Guy/Ching, Lincoln. 2003. Weeds of Hawaii‘s Pastures and Natural Areas; An Identification and Management Guide. College of Tropical Agriculture and Human Resources, University of Hawaii at Manoa. 184 pp.

Oppenheimer, Hank L./Bartlett, Randal T. 2002. New plant records from the main Hawaiian Islands. In: Evenhuis, Neal L. and Eldredge, Lucius G., eds. Records of the Hawaii Biological Survey for 2000. Part 2: Notes. Bishop Museum Occasional Papers. 69:1-14.

Starr, Forest/Starr, Kim/Loope, Lloyd L. 2006. New plant records from the Hawaiian Archipelago. In: Evenhuis, Neal L. and Eldredge, Lucias G., eds. Records of the Hawaii Biological Survey for 2004-2005. Part 1: Articles. Bishop Museum Occasional Papers 87:31-43.

U.S. Dept. Agr., Agr. Res. Serv. 2009. 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).