Hymenothrix dissecta is a North American species of flowering plants in the family Asteraceae known by the common names yellow ragweed and ragleaf bahia. It is native to the western United States as far north as the Black Hills of South Dakota and Wyoming, as well as in northern Mexico (Baja California, Chihuahua, Coahuila, Sonora).[3]
Hymenothrix dissecta can be found in several habitat types, from dry mountain slopes to roadsides. This is an annual or biennial herb producing a spindly, branching, erect stem variable in height from 20 centimeters to well over one meter. The stems are reddish and generally glandular. The small leaves are mostly located toward the base of the stem and are finely divided into linear lobes. The spreading inflorescence produces several flower heads, each lined with hairy, glandular phyllaries. Each head has a fringe of rounded yellow ray florets about half a centimeter long and a center of yellow disc florets. The fruit is a dark-colored achene 3 or 4 millimeters long. If there is any pappus it is small and scale-like.[4][5][6]
American botanist Asa Gray described the species as Amauria dissecta in 1849 from material collected in a valley between Guajuquilla and Mapimi in Chihuahua. It placed in the new genus Hymenothrix by Bruce Gregg Baldwin in 2016.[1]
Hymenothrix dissecta is a North American species of flowering plants in the family Asteraceae known by the common names yellow ragweed and ragleaf bahia. It is native to the western United States as far north as the Black Hills of South Dakota and Wyoming, as well as in northern Mexico (Baja California, Chihuahua, Coahuila, Sonora).
Hymenothrix dissecta can be found in several habitat types, from dry mountain slopes to roadsides. This is an annual or biennial herb producing a spindly, branching, erect stem variable in height from 20 centimeters to well over one meter. The stems are reddish and generally glandular. The small leaves are mostly located toward the base of the stem and are finely divided into linear lobes. The spreading inflorescence produces several flower heads, each lined with hairy, glandular phyllaries. Each head has a fringe of rounded yellow ray florets about half a centimeter long and a center of yellow disc florets. The fruit is a dark-colored achene 3 or 4 millimeters long. If there is any pappus it is small and scale-like.
American botanist Asa Gray described the species as Amauria dissecta in 1849 from material collected in a valley between Guajuquilla and Mapimi in Chihuahua. It placed in the new genus Hymenothrix by Bruce Gregg Baldwin in 2016.
Amauriopsis es un género monotípico de plantas fanerógamas perteneciente a la familia de las asteráceas. Su única especie Amauriopsis dissecta es originaria de Norteamérica.[1][2]
Es una planta bienal, (a veces florece en el primer año, a veces persiste), que alcanza un tamaño de 10-80 + cm de altura. Tallos erectos, generalmente ramificados distalmente, a veces desde las bases. Hojas generalmente basales y caulinares, pecioladas, láminas deltadas a ovadas u oblongas (a grandes rasgos), por lo general 1-2 lobuladas (sobre todo los lóbulos oblongos a obovados), los márgenes finales enteros o dentados. Las inflorescencias corimbiformes. Los involucros ± hemisféricos de 10 - 18 + mm de diámetro. brácteas persistentes, 12-21 + en ± 2 series. Disco floretes 30-80 +, bisexuales y fértiles; corolas amarillas.[3]
Se encuentra en los Estados Unidos y México.
Amauriopsis dissecta fue descrita por (A.Gray) Rydb. y publicado en North American Flora 34(1): 37. 1914.[4]
Amauriopsis: nombre genérico compuesto que deriva del griego y significa "parecido al género Amauria"[5]
dissecta: epíteto latíno que significa "finamente cortado"[6]
Amauriopsis es un género monotípico de plantas fanerógamas perteneciente a la familia de las asteráceas. Su única especie Amauriopsis dissecta es originaria de Norteamérica.
