What is a genus of North American plants in the aster tribe within the daisy family, Sorbus or Townsendia ?
Sorbus Sorbus is a genus of about 100–200 species of trees and shrubs in the rose family Rosaceae. Species of "Sorbus" ("s.l.") are commonly known as whitebeam, rowan, service tree, and mountain-ash. The exact number of species is disputed depending on the circumscription of the genus, and also due to the number of apomictic microspecies, which some treat as distinct species, but others group in a smaller number of variable species. Recent treatments treat "Sorbus" in a narrower sense to include only the pinnate leaved species of subgenus "Sorbus", raising several of the other subgenera to generic rank.
Vernonia Vernonia is a genus of about 1000 species of forbs and shrubs in the family Asteraceae. Some species are known as ironweed. Some species are edible and of economic value. They are known for having intense purple flowers. The genus is named for the English botanist William Vernon. There are numerous distinct subgenera and subsections in this genus. This has led some botanists to divide this large genus into several distinct genera. For instance, the "Flora of North America" only recognizes about 20 species in "Vernonia" sensu stricto, 17 of which are in North America north of Mexico, with the others being found in South America.