Pterocaulon
Pterocaulon is a genus of flowering plants in the sunflower family, native to North and South America and to Australasia. Blackroot is a common name for species native to North America.
The plants are perennial herbs, frequently densely covered with woolly hairs. The generic name means "winged stem," referring to the decurrent leaf bases that give the appearance of wings running down the sides of the stems.
; SpeciesPterocaulon alopecuroides - South America, Puerto Rico, Virgin IslandsPterocaulon angustifolium - Brazil, Argentina, Paraguay, UruguayPterocaulon balansae - Brazil, Argentina, Paraguay, UruguayPterocaulon cordobense - Brazil, Argentina, Paraguay, UruguayPterocaulon globuliflorus - Western Australia, Northern TerritoryPterocaulon lanatum - Brazil, Bolivia, Paraguay, SaltaPterocaulon lorentzii - Brazil, Argentina, Paraguay, Uruguay, BoliviaPterocaulon niveum - Western Australia, Northern TerritoryPterocaulon polypterum - Brazil, Argentina, UruguayPterocaulon polystachyum - Brazil, Argentina, Paraguay, UruguayPterocaulon purpurascens - Mato Grosso, Argentina, Paraguay, BoliviaPterocaulon pycnostachyum - United States Pterocaulon redolens - Indochina, Hainan, Orissa, Philippines, Maluku, New Guinea, eastern AustraliaPterocaulon rugosum - Brazil, Argentina, ParaguayPterocaulon serrulatum - Western Australia, Northern Territory, South AustraliaPterocaulon sphacelatum - AustraliaPterocaulon sphaeranthoides - Western Australia, Northern Territory, QueenslandPterocaulon spicatum - South AmericaPterocaulon verbascifolium - Western Australia, Northern Territory, QueenslandPterocaulon virgatum - Central + South America, West Indies, United States