''Haworthia retusa'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

s of the genus ''

Haworthia ''Haworthia'' is a large genus of small succulent plants endemic to Southern Africa (Mozambique, Namibia, Lesotho, Eswatini and South Africa). Like the aloes, they are members of the subfamily Asphodeloideae and they generally resemble mi ...

'' in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Asphodelaceae Asphodelaceae is a family of flowering plants in the order Asparagales. Such a family has been recognized by most taxonomists, but the circumscription has varied widely. In its current circumscription in the APG IV system, it includes about 40 ...

endemic Endemism is the state of a species being found 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 found elsew ...

to a very small area around Riversdale, in the

Western Cape The Western Cape is a province of South Africa, situated on the south-western coast of the country. It is the fourth largest of the nine provinces with an area of , and the third most populous, with an estimated 7 million inhabitants in 2020 ...

Province in

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...

. Growing to tall and broad, it is a

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

succulent In botany, succulent plants, also known as succulents, are plants with parts that are thickened, fleshy, and engorged, usually to retain water in arid climates or soil conditions. The word ''succulent'' comes from the Latin word ''sucus'', meani ...

with thick triangular leaves and small white tubular flowers held in tall

raceme A raceme ( or ) or racemoid is an unbranched, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are produced as the s ...

Etymology

The genus name ''Haworthia'' honors the British botanist

Adrian Hardy Haworth Adrian is a form of the Latin given name Adrianus or Hadrianus. Its ultimate origin is most likely via the former river Adria from the Venetic and Illyrian word ''adur'', meaning "sea" or "water". The Adria was until the 8th century BC the main ...

(1767–1833), while the species

epitheton An epithet (, ), also byname, is a descriptive term (word or phrase) known for accompanying or occurring in place of a name and having entered common usage. It has various shades of meaning when applied to seemingly real or fictitious people, di ...

''retusa'' derives from Latin and refers to the "retused" leaf-shape.

Description

Haworthia retusa Iconotype J Commelin 1701

A distinctive feature is the " retuse", deltoid, recurved shape of the leaves. The upturned, recurved face of each leaf forms a triangle, which is transparent (and often lined). The species can be easily recognised by its leaf-top windows, which are distinctively shiny. Plants grow as tight rosettes of thick, firm, fleshy, highly recurved/truncated leaves. It is usually a solitary rosette in the wild. In cultivation it can offset, and even form clumps.

Relatives

This species is one of the ''"retuse"'' species of ''

'', meaning that it usually grows sunken beneath the ground with its flattened leaves only showing on the surface. Its rosette of succulent leaves are turned back ("retuse") so as to provide a flat and level face, on the surface of the ground. In this form, it is similar to other retuse haworthias (e.g. '' Haworthia pygmaea'', '' Haworthia bayeri'', '' Haworthia springbokvlakensis'', ''

Haworthia mirabilis ''Haworthia mirabilis'' is a species of the genus ''Haworthia'' belonging to the family (biology), family Asphodelaceae. Etymology The genus name ''Haworthia'' honors the British botanist Adrian Hardy Haworth (1767–1833), while the species epi ...

'', ''

Haworthia emelyae ''Haworthia emelyae'' (synonym with ''Haworthia picta'') is a species of the genus ''Haworthia'' in the family Asphodelaceae, endemic to the Western Cape Province in South Africa. Description This species is one of the ''"retuse"'' species of ' ...

'', '' Haworthia mutica'', and ''

Haworthia magnifica ''Haworthia magnifica'' is a species of the genus ''Haworthia'' belonging to the family Asphodelaceae. It is popular as an ornamental in cultivation, especially in the form of its unique and colourful variety, ''"splendens"''. Etymology The gen ...

'').

Distribution

This species has a small area of natural distribution, being indigenous to an area around

Riversdale, Western Cape Riversdale ( af, Riversdal) is a town located on the N2 (South Africa), N2 highway between Cape Town and George, Western Cape, George on the Agulhas Coastal Plain of the southern Western Cape province of South Africa. It is an agricultural service ...

. Here it occurs from

Bredasdorp Bredasdorp is a town in the Southern Overberg region of the Western Cape, South Africa, and the main economic and service hub of that region. It lies on the northern edge of the Agulhas Plain, about south-east of Cape Town and north of Cape Agul ...

Mossel Bay Mossel Bay ( af, Mosselbaai) is a harbour town of about 99,000 people on the Southern Cape (or Garden Route) of South Africa. It is an important tourism and farming region of the Western Cape Province. Mossel Bay lies 400 kilometres east of the ...

. Its natural habitat is lower hills and flatter terrain. Its close relative, '' Haworthia turgida'', inhabits the steeper, rockier, more mountainous terrain to the north. It is a tendency that '' alooids'' adapt to steep, rocky cliffs by becoming smaller and more proliferous/clumping. This appears to be the case with ''H. turgida''. As the two species are otherwise extremely similar, and never overlap in distribution, it is likely that ''H. turgida'' is simply the mountainous form of ''H. retusa''.

Cultivation

''H. retusa'' is widely cultivated. In temperate regions it is normally grown under glass as it does not survive temperatures below freezing. In the UK it has gained the

Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr (Nort ...

’s

Award of Garden Merit The Award of Garden Merit (AGM) is a long-established annual award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions. History The Award of Garden Merit ...

Varieties

* ''Haworthia retusa'' var. ''nigra'' (M.B.Bayer) M.B.Bayer - south west

Cape Province The Province of the Cape of Good Hope ( af, Provinsie Kaap die Goeie Hoop), commonly referred to as the Cape Province ( af, Kaapprovinsie) and colloquially as The Cape ( af, Die Kaap), was a province in the Union of South Africa and subsequen ...

(

) * ''Haworthia retusa'' var. ''quimutica'' M.Hayashi - south west Cape Province * ''Haworthia retusa'' var. ''retusa'' (

autonym Autonym may refer to: * Autonym, the name used by a person to refer to themselves or their language; see Exonym and endonym * Autonym (botany), an automatically created infrageneric or infraspecific name See also * Nominotypical subspecies, in zo ...

) - south west Cape Province ( Riversdale) File:Haworthia retusa-HBG.jpg, "''H. retusa'' f. ''geraldii''", now a

synonym A synonym is a word, morpheme, or phrase that means exactly 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 all ...

of the type variety ''H. retusa'' var. ''retusa''.

References

retusa ''Retusa'' is a genus of very small head-shield sea snails or barrel-bubble snails, marine gastropod mollusks in the family Retusidae.Bouchet, P.; Gofas, S. (2013). ''Retusa'' T. Brown, 1827. Accessed through: World Register of Marine Species at ...

Flora of the Cape Provinces Endemic flora of South Africa Garden plants {{Asphodelaceae-stub