Echinopsis

Echinopsis
File:Echinopsis leucantha.jpg
Kingdom	Plantae
Family	Cactaceae
Subfamily	Cactoideae
Tribe	Cereeae
SubTribe	Trichocereinae
Genus	Echinopsis
Species
Notes	Taxonomy follows Joël Lodé (2015). Lodé treats Trichocereus, Lobivia, and Setiechinopsis as distinct genera.

Etymology

Derived from the Greek echinos (hedgehog or sea-urchin) and opsis (appearance), referring to the typical globose and spiny form of these plants.

Description

Echinopsis includes plants that are typically globose, often becoming elongated with age, and frequently caespitose (forming clumps).

• Stems: Feature ribs that are often protruding and more or less flattened.
• Flowers: Predominantly nocturnal and white, though some diurnal yellow or red forms exist. They are characterized by a very long, hairy floral tube and are pollinated by bees or hawk-moths (Sphingidae).
• Fruits and Seeds: Fruits are spherical to egg-shaped and more or less hairy. Seeds are small, black, and can be reticulate, striate, or papillose. Dispersal is primarily by ants (myrmecochory).

Habitat

Species grow in woodlands or grasslands, particularly in meadows with rocky outcrops. [cite: 1007] They are found on stony soils and in rock crevices, often under a humid climate with a distinct dry season. [cite: 1007] Altitudinal range is from 400 m up to 2400 m. [cite: 1007]

Distribution

Widespread across South America:

• Argentina, Bolivia, Brazil, Paraguay, and Uruguay. [cite: 1007]

Species

Following the restricted circumscription by Lodé (2015), the genus is reduced to approximately 23 species (excluding former Trichocereus and Lobivia): [cite: 1007]

• Echinopsis adolfofriedrichii
• Echinopsis albispinosa (syn. E. silvestrii)
• Echinopsis ancistrophora
• Echinopsis ayopayana
• Echinopsis boyuibensis
• Echinopsis bridgesii (Note: Not Trichocereus bridgesii)
  • Echinopsis bridgesii subsp. vallegrandensis
  • Echinopsis bridgesii subsp. yungasensis
• Echinopsis calochlora
• Echinopsis comarapana
• Echinopsis coronata
• Echinopsis eyriesii (Type species)
• Echinopsis hammerschmidii
• Echinopsis klingeriana
• Echinopsis leucantha
• Echinopsis mamillosa
• Echinopsis minuana
• Echinopsis oxygona
• Echinopsis pamparuizii
• Echinopsis rhodotricha
• Echinopsis rojasii
• Echinopsis semidenudata
• Echinopsis subdenudata
• Echinopsis sucrensis
• Echinopsis tubiflora

Taxonomy and Controversy

Lodé argues that the traditional "lumping" of Trichocereus and Lobivia into Echinopsis is unjustified because molecular studies show the group is not monophyletic. He maintains that:

• Trichocereus consists of larger, cereiform plants with massive nocturnal flowers. [cite: 1006]
• Lobivia generally features smaller plants with colorful diurnal flowers. [cite: 1006]
• Setiechinopsis is a distinct genus based on cytogenetic differences. [cite: 1006]