''Armatocereus rauhii'' is a tall, branched columnar species of

cactus A cactus (: cacti, cactuses, or less commonly, cactus) is a member of the plant family Cactaceae (), a family of the order Caryophyllales comprising about 127 genera with some 1,750 known species. The word ''cactus'' derives, through Latin, ...

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to the north of

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

on the western slopes of the

Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

Description

''Armatocereus'' is a tall, treelike cactus, bluish to greyish green in colour, usually with a trunk to about high followed by upright branches. Depending on the subspecies, it reaches a maximum height of , with branches thick. The stems have 6–12 ribs. The

areole In botany, areoles are small light- to dark-colored bumps on cactus, cacti out of which grow clusters of Thorns, spines, and prickles, spines. Areoles are important diagnostic features of cactus, cacti, and identify them as a family distinct fr ...

s bear about 6–7 short spines, only long – somewhat more spines in the case of subspecies ''balsasensis''. The flowers are long, carmine or purple in colour, with black to red spines on the floral tube.

Taxonomy

The species was first described by

Curt Backeberg Curt Backeberg (2 August 1894 in Lüneburg, Germany – 14 January 1966) was a German horticulturist especially known for the collection and classification of cacti. Biography He travelled extensively through Central and South America, and pu ...

in 1957. The specific epithet ''rauhii'' honours

Werner Rauh Werner Rauh (16 May 1913 in Niemegk – 7 April 2000 in Heidelberg) was a German biologist, botanist and author. Biography Born in the town of Niemegk near Bitterfeld, Rauh studied at Biology faculty at the University of Halle under the morp ...

. Two species described by Friedrich Ritter in 1981, ''Armatocereus balsasensis'' and ''Armatocereus arduus'', are included in this species, as

synonyms A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

of ''A. rauhii'' subsp. ''balsasensis'', by some sources. Other sources maintain ''A. arduus'' as a separate species, although noting that its taxonomic status is uncertain.

Subspecies

*''Armatocereus rauhii'' subsp. ''rauhii'' *''Armatocereus rauhii'' subsp. ''balsasensis'' (F.Ritter) Ostolaza – the subspecific epithet refers to the district of Balsas in Peru. This subspecies is taller, rather than , with thinner branches.

Distribution and habitat

''Armatocereus rauhii'' is

to the north of

. Within the country, the stated distribution of the species as a whole and of the subspecies varies by source, but centres on the regions of Amazonas,

Cajamarca Cajamarca (), also known by the Quechua name, ''Kashamarka'', is the capital and largest city of the Cajamarca Region as well as an important cultural and commercial center in the northern Andes. It is located in the northern highlands of Per ...

and Lambayeque. It may also include the regions of

Ancash Ancash (; ) is a department and region in western Peru. It is bordered by the departments of La Libertad on the north, Huánuco and Pasco on the east, Lima on the south, and the Pacific Ocean on the west. Its capital is the city of Huaraz, an ...

and

Piura Piura is a city in northwestern Peru, located north of the Sechura Desert along the Piura River. It is the capital of the Piura Region and the Piura Province. Its population was 484,475 as of 2017 and it is the 7th most populous city in Peru. ...

. The species is found in dry valleys, rocky slopes and scrubland on the western side of the Andes, and has been reported as occurring at altitudes of , with the higher altitudes being further south.

Conservation

The 2013 assessment in the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological ...

did not differentiate between the subspecies, rating the species as whole as of "least concern". Earlier, ''A. rauhii'' subsp. ''balsasensis'' was rated as "vulnerable".

References

{{Taxonbar, from=Q679427 rauhii Endemic flora of Peru Cacti of South America