Cochlearia (scurvy-grass or spoonwort) is a genus of about 30 species of annual and perennial herbs in the family Brassicaceae. They are widely distributed in temperate and arctic areas of the northern hemisphere, most commonly found in coastal regions, on cliff-tops and salt marshes where their high tolerance of salt enables them to avoid competition from larger, but less salt-tolerant plants; they also occur in alpine habitats in mountains and tundra. They form low, rounded or creeping plants, typically 5–20 cm tall. The leaves are smoothly rounded, roughly spoon-shaped (the scientific name Cochlearia derives from the Latinized form, cocleare, of the Greek κοχλιάριον, kokhliárion, a spoon; this a diminutive of κόχλος, kókhlos, seashell), or in some species, lobed; typically 1–5 cm long, and with a fleshy texture. The flowers are white with four petals and are borne in short racemes. Selected species About 30 species are usually accepted; several others usually treated as subspecies of C. officinalis are accepted as distinct species by some botanists. Cochlearia acutangula Cochlearia aestuaria – Estuarine scurvy-grass Cochlearia alatipes Cochlearia anglica – English scurvy-grass Cochlearia aragonensis Cochlearia changhuaensis Cochlearia cyclocarpa – Roundfruit scurvy-grass Cochlearia danica – Early or Danish scurvy-grass Cochlearia fenestrata – Arctic scurvy-grass Cochlearia formosana Cochlearia excelsa Cochlearia fumarioides Cochlearia furcatopilosa Cochlearia glastifolia Cochlearia groenlandica – Greenland scurvy-grass Cochlearia henryi Cochlearia hui Cochlearia lichuanensis Cochlearia longistyla Cochlearia megalosperma Cochlearia microcarpa Cochlearia oblongifolia – East Asian scurvy-grass Cochlearia officinalis – Common scurvy-grass (including C. excelsa, C. pyrenaica, C. scotica) Cochlearia paradoxa Cochlearia rivulorum Cochlearia rupicola Cochlearia sessilifolia – Sessile-leaved or Alaskan scurvy-grass Cochlearia sinuata Cochlearia tatrae Cochlearia tridactylites – Three-fingered scurvy-grass Cochlearia warburgii Two species formerly included in the genus Cochlearia are now usually treated in separate genera: Horseradish Armoracia rusticana (previously Cochlearia armoracia) Wasabi Wasabia japonica (previously Cochlearia wasabi) Cook's scurvy grass, Lepidium oleraceum, was used by James Cook to prevent scurvy, but is now almost extinct. History and uses Scurvy-grass is edible raw and cooked, with a flavour similar to cress. The leaves are rich in vitamin C, which cures scurvy, a deficiency disease resulting from a lack of fresh vegetables in the diet. The plant was frequently eaten in the past by sailors suffering from scurvy after returning from long voyages. The first-century writer Pliny the Elder (A.D. 23–79) writes in his Naturalis Historia (Natural History) about a disease suffered by Roman soldiers in Germany. Their symptoms resemble those of scurvy,