Hypochoeris (also written Hypochaeris) is a genus of flowering plants in the daisy family Asteraceae, order Asterales. The genus comprises annual and perennial herbs typically bearing solitary or branched stems topped with flower heads made up entirely of yellow ray florets — the ligulate head form characteristic of many members of the tribe Cichorieae. Because of this appearance, numerous species are colloquially called cat's ear or false dandelion, as they are easily mistaken for true dandelions (Taraxacum).
Species counts vary among authorities, with estimates ranging from roughly 50 to around 100 species. The centre of diversity lies in South America, where the great majority of species are endemic. A smaller contingent of species is native to Eurasia and North Africa. Two species — Hypochoeris radicata (common cat's ear) and Hypochoeris glabra (smooth cat's ear) — have spread widely as introduced weeds beyond their native Eurasian ranges and are now naturalised across much of the world, including the Americas, Australia, and New Zealand.
Etymology
The genus name Hypochoeris derives from the ancient Greek ὑπό (hypo, "under") and χοῖρος (choiros, "young pig"). The precise reasoning behind the name is not fully documented, though it has been suggested it may relate to pigs rooting under the ground for the plant's roots.
Distribution
Most Hypochoeris species are native to South America, which represents the centre of diversity for the genus. A number of species also occur naturally in Eurasia and North Africa. Two Eurasian species, H. radicata and H. glabra, have become widely naturalised as agricultural and roadside weeds across temperate regions worldwide.
Taxonomy Notes
The genus is sometimes spelled Hypochaeris — both spellings appear in the literature and refer to the same genus; Hypochoeris is the form used by GBIF. The group belongs to the tribe Cichorieae within Asteraceae. Molecular phylogenetic work using nuclear rDNA internal transcribed spacers has been used to investigate relationships among species and infer chromosomal evolution within the genus.
