{{Short description|Genus of plants from Argentina}} {{Automatic taxobox | image = Acanthocalycium violaceum.jpg | image_caption = ''Acanthocalycium spiniflorum'' | display_parents = 2 | taxon = Acanthocalycium | authority = [[Curt Backeberg|Backeb.]]<ref name=POWO_295863-2/> | subdivision_ranks = Species | subdivision = [[#Species|See text]]. |type_species =''[[Acanthocalycium spiniflorum]]'' }}
'''''Acanthocalycium''''' is a [[genus]] of [[cactus]] consisting of several species from [[Argentina]], [[Bolivia]], [[Brazil]], [[Paraguay]] and [[Uruguay]].<ref name=POWO_295863-2/> The taxon name comes from [[Greek language|Greek]] ''akantha'' (meaning ''prickly'') and ''kalyx'' (meaning ''buds''), which refers to the spines on the [[floral tube]]s.<ref name="Eggli Newton 2004">{{cite book | last = Eggli | first = U. | last2 = Newton | first2 = L.E. | title = Etymological Dictionary of Succulent Plant Names | publisher = Springer Berlin Heidelberg | year = 2004 | isbn = 978-3-540-00489-9 | url = https://books.google.com/books?id=u2n5vusQ1DEC&pg=PA1 | access-date = 20 September 2018 | page = 1 }}</ref>
==Description== These plants are [[wikt:globose|globose]] to [[wikt:elongate|elongate]], with numerous ribs on the spiny [[Plant stem|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.
[[Flower]]s 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.<ref name="Anderson Eggli Anderson 2005 p. 67–68">{{cite book | last=Anderson | first=Edward F. | last2=Eggli | first2=Urs | last3=Anderson | first3=Edward F. | title=Das große Kakteen-Lexikon | publisher=Ulmer | publication-place=Stuttgart (Hohenheim) | date=2005 | isbn=3-8001-4573-1 | language=de | page= 67–68}}</ref>
== Taxonomy == ''Spinicalycium'' <small>[[Alberto Vojtech Frič|Fric]]</small> (nom. inval.) has been brought into [[synonym (taxonomy)|synonymy]] with this genus. Besides, the genus ''Acanthocalycium'' has been periodically included in the genus ''[[Echinopsis]]''.{{citation needed|date=October 2023}}
=== Species === {{As of|2025|October}}, [[Plants of the World Online]] accepted the following species:<ref name=POWO_295863-2>{{Cite POWO|title=''Acanthocalycium'' Backeb..|id=295863-2|access-date=2023-10-10|mode=cs1}}</ref> {| class="wikitable" |- ! Image !! Scientific name !! Distribution |- |[[File:Echinopsis klingeriana1PCJO.jpg|120px]] || ''[[Acanthocalycium klinglerianum]]'' <small>(Cárdenas) Lodé</small> || Bolivia |- |[[File:Echinopsis leucanthus.jpg|120px]] || ''[[Acanthocalycium leucanthum]]'' <small> (Gillies ex Salm-Dyck) Schlumpb.</small> || Argentina |- |[[File:Echinopsis rhodotricha K. Schumann in habitat.JPG|120px]] || ''[[Acanthocalycium rhodotrichum]]'' <small>(K.Schum.) Schlumpb.</small> || E. Bolivia to W. Central Brazil and Uruguay |- |[[File:Acanthocalycium violaceum 7.JPG|120px]] ||''[[Acanthocalycium spiniflorum]]'' <small>(K.Schum.) Backeb.</small> || Argentina |- |[[File:Acanthocalycium thionanthum.jpg|120px]] ||''[[Acanthocalycium thionanthum]]'' <small>(Speg.) Backeb.</small> || Argentina |- |}
== References == {{Reflist}} * [[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 [[File:Gymnocalycium (acanthocalycium) violaceum.JPG|250px|thumb|left|The flower of ''Acanthocalycium spiniflorum'']]
{{Taxonbar|from=Q133858}}
[[Category:Acanthocalycium| ]] [[Category:Cereeae genera]]