- Name also: Russian Thistle, Prickly Glasswort, Tumbleweed, Glasswort
- Latin synonym: Salsola kali, Salsola turgidum
- Family: Amaranth Family – Amaranthaceae
(formerly Goosefoot Family – Chenopodiaceae)
- Growing form: Annual herb. Spreading taproot
- Height: 5–30 cm (2–12 in.). Stems bushy, much-branched
- Flower: Regular, small. White or membranous perianth consists of 5 segments, ca. 4 mm (0.2 in.) long in fruit. Broad midrib of tepal extends beyond blade as a spine-like tip. Flowers mostly solitary in the axils.
- Leaves: Lower alternate, upper opposite, stalkless. Blade fleshy, hairless or hairy, more than 1 mm (0.04 in.) wide, ca. 20 mm (0.8 in.) long, linear to thread-like, grooved at the base, spine-tipped.
- Fruit: Brown, cup-shaped, one-seeded achene. Sepals which have a broad longitudinal appendage at the dorsal side surround the achene.
- Habitat: Sandy seashores, seaweed heaps.
- Flowering time: July–August.
- Endangerment: Endangered, protected in all of Finland.
In Finland there are two saltwort species, both annuals. Prickly saltwort is much more common although occurs on a more restricted area. The eastern saltwort (Kali tragus, also Salsola tragus) differs from the prickly one in having softer and relatively narrower leaves and untipped tepals (also the midrib is obscure).
Prickly saltwort is not a halophyte like glassworts (Salicornia spp.) or seablites (Suaeda spp.). It prefers seaweed heaps or sand further up on the shore. It is also a pioneer species of sand dunes that by binding the sand establishes the first dune stage.
The older generic name Salsola (from Latin Salsus) means salty and the older specific epithet and today’s generic name kali means ashes of a sodium-rich plant. Indeed, prickly saltwort has been used for making soda in France and Spain.