Hypochaeris is a genus of annual and perennial herbs in the daisy family (Asteraceae), order Asterales. The genus comprises an estimated 50 to 100 species, the majority of which are native to temperate South America, with additional species occurring in the Mediterranean region, other parts of Europe, and North Africa. Several species have naturalised widely outside their native range, notably in Australia, New Zealand, and North America.
Members of Hypochaeris are taprooted rosette herbs, typically with basal leaves that spread flat and are toothed to pinnatifid in outline; stem leaves are few or absent. The flowering stems are simple or sparsely branched and bear solitary heads at their tips. The involucre is cylindrical to cone-shaped, with bracts arranged in two to five series, and the receptacle is flat and furnished with scales. All florets are ligulate (strap-shaped), most commonly bright yellow, though white-flowered species such as H. albiflora occur. The achenes are cylindrical, ribbed, and roughened, with the inner achenes typically bearing a slender beak; the pappus consists of one or two rows of plumose (feathery) bristles, sometimes accompanied by an outer row of simple bristles.
The genus is frequently confused with dandelions (Taraxacum), earning several species the common name "false dandelion." The most widespread species, Hypochaeris radicata (common cat's ear), is recognised across temperate regions of the world as a persistent grassland and lawn weed.
The genus name is also spelled Hypochoeris, the form used by Linnaeus in 1754, which GBIF treats as a synonym.
Etymology
The genus name Hypochaeris derives from the Greek words ὑπό (hypo, "under") and χοῖρος (choiros, "young pig"), a reference recorded since antiquity, though the precise connection to swine is obscure; one interpretation suggests pigs were known to root up the plants.
Distribution
Most Hypochaeris species are native to temperate South America, with a secondary centre of diversity in the Mediterranean region and other parts of Europe and Asia. A smaller number of species occur in North Africa. Several species, most prominently H. radicata and H. glabra, have been introduced beyond their native ranges and are now naturalised throughout Australia, New Zealand, western North America, and parts of East Asia.
Ecology
Species of Hypochaeris grow in open habitats including grasslands, meadows, roadsides, lawns, and disturbed ground. The taprooted rosette growth form is well suited to mown or grazed swards. Hypochaeris radicata is one of the most successful lawn and pasture weeds of the temperate world, tolerating repeated mowing because the growing point remains close to the ground.
