Baccharis
Baccharis is a genus of perennials and shrubs in the aster family (Asteraceae). They are commonly known as baccharises but sometimes referred to as "brooms", because many members have small thin leaves resembling the true brooms. They are not at all related to these however, but belong to an entirely different lineage of eudicots. "B. halimifolia" is commonly known as "groundsel bush", however true groundsels are found in the genus "Senecio". "Baccharis", with over 500 species, is the largest genus in the Compositae. It is found throughout the Americas, distributed mainly in the warmer regions of Brazil, Argentina, Colombia , Chile and Mexico, with "B. halimifolia" ranging northward along the Atlantic Coast to the southern tip of Nova Scotia in Canada. If present, the leaves of "Baccharis" are borne along the stems in alternate fashion. Flowers are usually white or pinkish. There are no ray flowers, but many disk flowers which are either staminate or pistillate. Some species of "Baccharis" are toxic to animals; in particular, consumption of "B. coridifolia" may lead to necrosis in the gastrointestinal tract of cattle, horses, sheep, and rabbits. The genus "Baccharis" is named after Bacchus (Dionysus), the Roman god of wine. Classification. "Baccharis" is  related to the genera "Archibaccharis" and "Heterothalamus". All baccharis are dioecious except Baccharis monoica. Ecology. "Baccharis" are used as food plants by the larvae of some Lepidoptera species, such as the swift moths "Phymatopus californicus" and "P. hectoides". Those of the leaf-miner moths "Bucculatrix dominatrix" and "B. seperabilis" feed exclusively on Bush Baccharis ("B. pilularis"), "B. ivella" has been found on Eastern Baccharis, and "B. variabilis" is a polyphagous species which has been recorded on various "Baccharis". The "Coleophora" case-bearers "C. linosyridella" and "C. viscidiflorella" are polyphagous species whose larvae have been recorded on the Bush Baccharis as  well as other plants. Caterpillars of the owlet moth "Schinia ocularis" feed exclusively on Broom Baccharis ("B. sarothroides"). Uses. Several species of "Baccharis" are of interest for cultivation, as the dense but flexible stem structure makes for a good windbreak. Plants of this genus are rich in terpenes, and some are used in native or folk medicine. One that has been specifically described from Chilean and Argentinean "Baccharis" is viscidone. "Baccharis" flowers are rich in nectar, and several species are good honey plants. Particularly "B. dracunculifolia" is highly esteemed by beekeepers. Conservation. A few "Baccharis" species (especially from the northern  Andes) are almost extinct due to habitat destruction. The northernmost occurrence of "B. halimifolia", in Nova Scotia, Canada, is also receiving conservation attention. Invasiveness. Some "Baccharis" species, particularly Eastern baccharis ("B. halimifolia"), have become invasive weeds in places such as Australia and Spain, where they are not native. Selected species. For the complete list of species see List of Baccharis species. Formerly placed in "Baccharis". The following species are among the many that were considered to belong within "Baccharis" but are now classified in other genera: