Salsola tragus  (S. iberica, S. pestifer) Russian thistle Chenopodiaceae SATR*; Q, i;


Salsola tragus.Copyright Mel Harte

Salsola tragus.Copyright Mel Harte (Accessed 5/2014).

Salsola tragus is an annual, C4 herb (Jacobs 2001), 10-60 cm tall, from at deep taproots with many lateral branches, C4 metabolism utilizes CO2 and water more efficiently than more common C3 metabolism (Crompton and Bassett 1985), a spiny tumbleweed, much branched, stems often striped with reddish or purple; plant becoming rigid and forming an open ball, to 1 m diameter (usually less), breaking off and rolling over open ground to disperse seeds. 

Leaves succulent, linear, to 6 cm long, 0.1cm wide near base, spine-tipped, becoming smaller upward eventually as spiny bracts. 

Flowers small, solitary or few together in upper axils, no petals, sepals, 5, soft, papery, midvein obscure; wind pollinated June-July, but is also self-fertile. 

Fruit dry, calyx expanding to 1 cm, folded over, seeds snail-shaped, black, 1.5 mm, seed matures Aug.-Sept. (in Canada, probably into Oct in NYC). One plant can produce over 100,000 seeds. Seeds eaten by birds. Seed germination rate drops to 0.5% after the first spring. Seedling emerge in March-April, even when nighttime temperatures are below freezing (Crompton and Bassett 1985). Russia. 

Salsola tragus.Liz

Salsola tragus.Liz (Accessed 5/2014).

Wetland status: FACU-. 

Frequency in NYC: Very infrequent in the NY Metro region, in dry, open areas. 

Origin: Eurasia. 

Habitat: Favors well drained alkaline soil and sandy, gravelly substrates. 

Notes: Russian thistle is eaten by the larvae of many lepidoptera including: the cutworms(Dart moths) Euxoa brevipennisE. tristiculaAgrostis orthogoniaCingilia catenaria (Chain-dotted geometer) (Covell 1984). it is also attacked by the curl top virus and a number of fungi (Crompton and Bassett 1985). Much like S. kali which is a maritime plant with spine-tipped sepals.