Echinopsis (Cactaceae)
This South American genus has around 60 species, although hundreds have been named. Some may be found under the generic names Trichocereus, Lobivia, Helianthocereus, Chamaecereus, and other smaller genera. Some are large and woody enough to be used in building; others contain mescaline. In some species the flowers are open in the day, others open at night. Many species are cultivated, and hybrids are grown in collections.