{{Short description|Genus of cacti}} {{Automatic taxobox |image = Oreocereus celsianus. Cactus.JPG |image_caption = ''[[Oreocereus celsianus]]'' |display_parents = 2 |taxon = Oreocereus |authority = ([[A.Berger]]) [[Riccob.]] |subdivision_ranks = Species |subdivision = [[#Species|See text]]. |type_species =''[[Oreocereus celsianus]]'' |synonyms = {{Genus list |Arequipa|Britton & Rose |Arequipiopsis|Kreuz. & Buining |Moraquipa|Rüd.Baumgärtner |Morawetzia|Backeb. }} |synonyms_ref = <ref name="Plants of the World Online 2020 m892"/> }}
'''''Oreocereus''''' is a [[genus]] of [[cactus|cacti]] ([[Family (taxonomy)|family]] Cactaceae), known only from high altitudes of the [[Andes]]. Its name means "mountain [[Cereus (plant)|cereus]]", formed from the Greek prefix ''{{transliteration|grc|[[wikt:oro-|oreo-]]}}'' ({{lang|grc|ὀρεο-}}, mountain)<ref>{{OED|oreography}}</ref> and the [[Neo-Latin]] ''{{lang|la|cereus}}'', meaning wax or torch.
==Description== The species of the genus Oreocereus grow shrubby, branching only sparsely from the base and reach heights of growth of 2 to 3 meters. Trunks are rarely formed. The erect, pendulous or rarely extended cylindrical shoots are notched or warty between the ribs. The areoles often have long white hairs and dense spines. As they are covered with woolly white fuzz (modified spines), a few species in this genus are sometimes known as the '''old-man cactus''',<ref>University of Vermont, [http://pss.uvm.edu/pss123/cacesp.html Indoor Plants]</ref><ref>{{cite book|author1=Barry Walker|author2=Huw Lloyd|title=Peruvian Wildlife: A Visitor's Guide to the Central Andes|url=https://books.google.com/books?id=fWFHDhLnylAC&pg=PA23|year=2007|publisher=Bradt Travel Guides|isbn=978-1-84162-167-8|page=23}}</ref> a generic name that also refers to ''[[Cephalocereus senilis]]'' or ''[[Espostoa lanata]]''. More rarely, the '''old man of the mountain''' is also used for some species.{{refn|group=nb|“[...] hairy cacti in cultivation include: golden old man (''[[Cephalocereus chrysacanthus|C. chrysacanthus]]''), old woman (''[[Mammillaria hahniana]]''), Chilean old lady (''[[Eriosyce senilis|Neoporteria senilis]]''), and '''old man of the mountain (''[[Oreocereus trollii|Borzicactus trollii]]'')'''.”<ref>''Encyclopædia Britannica'' (1991), entry ‘old-man cactus’.</ref> [emphasis added, ''B. trollii'' being an old name for ''O. trollii''].<ref name="Mabberley2008">{{cite book|author=D. J. Mabberley|title=Mabberley's Plant-book: A Portable Dictionary of Plants, Their Classifications, and Uses|url=https://books.google.com/books?id=9RyKKHtwXUYC&pg=PA608|date=2008-05-01|publisher=Cambridge University Press|isbn=978-0-521-82071-4|page=608}}</ref>}}
The tubular to funnel-shaped, more or less radially symmetrical, orange to red to violet flowers arise near the shoot tip, or sometimes from the terminal cephalium, and open during the day. The flower-tube is straight to slightly curved and sometimes laterally compressed. The numerous areoles on the pericarpel and the flower tube are hairy. The spherical to oblong fruits contain broadly oval, dull or shiny black seeds.<ref name="Backeberg 1984 p. 2619–2629">{{cite book | last=Backeberg | first=Curt | title=Die Cactaceae | date=January 1984 | isbn=3-437-30383-X | language=de | pages= 2619–2629| publisher=Fischer }}</ref><ref name="Anderson Eggli 2005 p. 482">{{cite book | last1=Anderson | first1=Edward F. | last2=Eggli | first2=Urs | title=Das grosse Kakteen-Lexikon | date=2005 | isbn=3-8001-4573-1 | language=de | page=482| publisher=Ulmer }}</ref>
==Species== {{As of|2025|October}}, [[Plants of the World Online]] accepts the following species:<ref name="Plants of the World Online 2020 m892">{{cite web | title=''Oreocereus'' Riccob. — Plants of the World Online | website=Plants of the World Online | date=2020-02-03 | url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:30004843-2 | access-date=2023-09-29}}</ref> {| class="wikitable" |- ! Image !! Scientific name !! Distribution |- |[[File:Caktus, flowering, SG.jpg|120px]] || ''[[Oreocereus celsianus]]'' {{small|(Lem. ex Salm-Dyck) A.Berger ex Riccob.}} || Peru, Bolivia, Argentina (Jujuy) |- |[[File:Oreocereus doelzianus (8415020795).jpg|120px]] || ''[[Oreocereus doelzianus]]'' {{small|(Backeb.) Borg}} ||Peru. |- |[[File:Arequipa rettigii 10038.jpg|120px]]|| ''[[Oreocereus hempelianus]]'' {{small|(Gürke) D.R.Hunt}} || Peru to Chile (Tarapacá) |- |[[File:Oreocereus leucotrichus.jpg|120px]] || ''[[Oreocereus leucotrichus]]'' {{small|(Phil.) Wagenkn.}} ||Chile, Peru |- |[[File:Oreocereus pseudofossulatus 02.jpg|120px]] || ''[[Oreocereus pseudofossulatus]]'' {{small| D.R.Hunt}} || Bolivia. |- |[[File:Oreocereus ritteri.jpg|120px]]|| ''[[Oreocereus ritteri]]'' {{small|Cullmann}} || Peru |- | || ''[[Oreocereus tacnaensis]]'' {{small|F.Ritter}} ||Peru |- |[[File:Ses Salines - Botanicactus - Oreocereus trollii 02 ies.jpg|120px]] || ''[[Oreocereus trollii]]'' {{small|(Kupper) Backeb.}} || Argentina, Bolivia |- |}
==References== {{Reflist|group=nb}} {{Reflist}}
==External links== *{{Commons category-inline|Oreocereus|''Oreocereus''}} *{{Wikispecies-inline|Oreocereus|''Oreocereus''}} {{Taxonbar|from=Q134007}} {{Authority control}} [[Category:Cereeae]] [[Category:Cacti of South America]] [[Category:Flora of the Andes]] [[Category:Cereeae genera]]