Echinopsis

Echinopsis is a genus of cacti in the family Cactaceae, native to South America. The genus comprises about 70 to 80 species, though exact numbers vary with taxonomic treatment. Echinopsis species range from small globose forms to tall columnar shrubs, with ribbed stems and spines that vary from absent to long and needle-like. The most distinctive feature is the large, showy flowers that appear at or near the apex; flowers are typically funnel-shaped and can be white, pink, red, or yellow. Flowering is usually in spring or summer, and some species open at night, attracting moths, while others bloom during the day for bees or hummingbirds.

Taxonomy and nomenclature: Echinopsis has undergone extensive revision. In some classifications, many species formerly placed in Trichocereus or other genera are now included in Echinopsis, leading to differences among authorities about species limits and names.

Distribution: Echinopsis is native to a broad swath of South America, including Argentina, Bolivia, Brazil, Chile, Paraguay, Peru, and Uruguay. Habitats range from Andean highlands to plains and deserts, often in well-drained soils with strong sunlight.

Cultivation: They are widely grown as ornamentals. Grow them in bright light, with well-draining potting mix and sparse irrigation during the growing season; allow a dry rest in winter in many regions. They tolerate warm temperatures but are usually not frost-hardy. Propagation is commonly by offsets or cuttings.

Notes: Some species, such as those formerly known as Trichocereus pachanoi (San Pedro), contain psychoactive alkaloids and are subject to regulatory controls in several countries.