en Acanthocalycium

Acanthocalycium
	Acanthocalycium spiniflorum
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Order:	Caryophyllales
Family:	Cactaceae
Subfamily:	Cactoideae
Tribe:	Cereeae
Subtribe:	Trichocereinae
Genus:	Acanthocalycium; Backeb.
Type species
	Acanthocalycium spiniflorum;
Species
	See text.

Acanthocalycium is a genus of cactus consisting of several species from Argentina, Bolivia, Brazil, Paraguay and Uruguay.^[1] The taxon name comes from Greek akantha (meaning prickly) and kalyx (meaning buds), which refers to the spines on the floral tubes.^[2]

Description

These plants are globose to elongate, with numerous ribs on the spiny stems columnar stem succulents up to 60 cm high and 20 cm in diameter. The plants usually remain unbranched or branch slightly from the bases. The areoles, which stand on up to 20 ribs, have many spines up to about 8 cm long, which are only indistinctly divided into edge and central spines.

Flowers range from yellow to orange or white to pink or magenta and open during the day. The funnel-shaped flowers, formed by areoles near the apex, have scales on the outside that taper into sharp thorns. This feature is typical of the genus Acanthocalycium and only occurs in it. Inside, the area of the flower containing the ovary (ovary) is protected with a ring of hairs.^[3]

Taxonomy

Spinicalycium Fric (nom. inval.) has been brought into synonymy with this genus. Besides, the genus Acanthocalycium has been periodically included in the genus Echinopsis.^{[citation needed]}

Species

As of October 2023^[update], Plants of the World Online accepted the following species:^[1]

Image	Scientific Name	Distribution
	Acanthocalycium klinglerianum (Cárdenas) Lodé	Bolivia
	Acanthocalycium leucanthum (Gillies ex Salm-Dyck) Schlumpb.	Argentina
	Acanthocalycium rhodotrichum (K.Schum.) Schlumpb.	E. Bolivia to W. Central Brazil and Uruguay
	Acanthocalycium spiniflorum (K.Schum.) Backeb.	Argentina
	Acanthocalycium thionanthum (Speg.) Backeb.	Argentina

References

^ ^a ^b ^c "Acanthocalycium Backeb." Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 2023-10-10.
^ Eggli, U.; Newton, L.E. (2004). Etymological Dictionary of Succulent Plant Names. Springer Berlin Heidelberg. p. 1. ISBN 978-3-540-00489-9. Retrieved 20 September 2018.
^ Anderson, Edward F.; Eggli, Urs; Anderson, Edward F. (2005). Das große Kakteen-Lexikon (in German). Stuttgart (Hohenheim): Ulmer. p. 67–68. ISBN 3-8001-4573-1.

Edward F. Anderson, The Cactus Family (Timber Press, 2001), pp. 105–106
Willy Cullmann, Erich Götz & Gerhard Gröner, The Encyclopedia of Cacti (Alphabooks, 1086). pp. 124–125

[POWO_295863-2-1] "Acanthocalycium Backeb." Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 2023-10-10.

[Eggli_Newton_2004-2] Eggli, U.; Newton, L.E. (2004). Etymological Dictionary of Succulent Plant Names. Springer Berlin Heidelberg. p. 1. ISBN 978-3-540-00489-9. Retrieved 20 September 2018.

[Anderson_Eggli_Anderson_2005_p._67–68-3] Anderson, Edward F.; Eggli, Urs; Anderson, Edward F. (2005). Das große Kakteen-Lexikon (in German). Stuttgart (Hohenheim): Ulmer. p. 67–68. ISBN 3-8001-4573-1.

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