The

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

''Quaqua'' falls within the tribe of plants known collectively as stapeliads. All stapeliads, including ''Quaqua'', are

Old World The "Old World" is a term for Afro-Eurasia that originated in Europe , after Europeans became aware of the existence of the Americas. It is used to contrast the continents of Africa, Europe, and Asia, which were previously thought of by the ...

stem succulent Stem succulents are fleshy succulent columnar shaped plants which conduct photosynthesis mainly through their stems rather than their leaves.Frerea indica, a Stem Succulent CAM Plant with Deciduous C₃ Leaves, Otto L. Lange and Margit Zuber, Oeco ...

s. Species of the genus ''Quaqua'' are exceptionally varied and

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 southwestern

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

, and locally very common in

Namaqualand Namaqualand (khoekhoe: "Nama-kwa" meaning Nama Khoe people's land) is an arid region of Namibia and South Africa, extending along the west coast over and covering a total area of . It is divided by the lower course of the Orange River into ...

Description

Species of ''Quaqua'' are usually characterised by having stout, firm, 4 or 5-sided

stem Stem or STEM may refer to: Plant structures * Plant stem, a plant's aboveground axis, made of vascular tissue, off which leaves and flowers hang * Stipe (botany), a stalk to support some other structure * Stipe (mycology), the stem of a mushro ...

s bearing conical

tubercle In anatomy, a tubercle (literally 'small tuber', Latin for 'lump') is any round nodule, small eminence, or warty outgrowth found on external or internal organs of a plant or an animal. In plants A tubercle is generally a wart-like projection ...

s which often have a tough, tapering spike at their ends. A few species lack the spikes or have smoothly rounded tubercles. ''Quaqua''

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...

s are distinctive from those of other southern African stapeliads for their numerous

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

s emerging from each stem, especially closer to the ends. There are often ten along each stem, vertically arranged in distichous series. The flowers of some species are sweet smelling (faintly of

honey Honey is a sweet and viscous substance made by several bees, the best-known of which are honey bees. Honey is made and stored to nourish bee colonies. Bees produce honey by gathering and then refining the sugary secretions of plants (primar ...

lemon The lemon (''Citrus limon'') is a species of small evergreen trees in the flowering plant family Rutaceae, native to Asia, primarily Northeast India (Assam), Northern Myanmar or China. The tree's ellipsoidal yellow fruit is used for culin ...

), attractive and rather small (between 7 and 15 mm in diameter). The flowers of other species however, are larger, reaching a maximum diameter of 27 mm and are dark,

papillate This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary o ...

, and usually have a repulsive odor of

urine Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excretion, excreted from the body through the urethra. Cel ...

excrement Feces ( or faeces), known colloquially and in slang as poo and poop, are the solid or semi-solid remains of food that was not digested in the small intestine, and has been broken down by bacteria in the large intestine. Feces contain a relati ...

. These species are pollinated by flies. File:Quaqua pillansii - rooinek western cape.jpg, ''

Quaqua pillansii The genus ''Quaqua'' falls within the tribe of plants known collectively as stapeliads. All stapeliads, including ''Quaqua'', are Old World stem succulents. Species of the genus ''Quaqua'' are exceptionally varied and endemic to southwestern A ...

'', from the

Little Karoo The Karoo ( ; from the Afrikaans borrowing of the South Khoekhoe !Orakobab or Khoemana word ''ǃ’Aukarob'' "Hardveld") is a semi-desert natural region of South Africa. No exact definition of what constitutes the Karoo is available, so its ext ...

, has smooth, erect grey stems File:Quaqua ramosa - E Barrydale.jpg, ''

Quaqua ramosa The genus ''Quaqua'' falls within the tribe of plants known collectively as stapeliads. All stapeliads, including ''Quaqua'', are Old World stem succulents. Species of the genus ''Quaqua'' are exceptionally varied and endemic to southwestern ...

'', from the western Karoo, locally called "Ou Ram" ("old ram"), is unusual in having rounded tubercles instead of the typical quaqua spikes

Distribution

In distribution, the genus ''Quaqua'' is restricted to the western (winter-rainfall) region of

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 ...

Namibia Namibia (, ), officially the Republic of Namibia, is a country in Southern Africa. Its western border is the Atlantic Ocean. It shares land borders with Zambia and Angola to the north, Botswana to the east and South Africa to the south and ea ...

. Its distribution closely mirrors that of related genus ''

Tromotriche ''Tromotriche'' is a genus of plant in family Apocynaceae. It is native to southern Africa.Gibbs Russell, G. E., W. G. M. Welman, E. Retief, K. L. Immelman, G. Germishuizen, B. J. Pienaar, M. Van Wyk & A. Nicholas. 1987. List of species of southe ...

''.

Species

Plants of the World Online Plants of the World Online (POWO) is an online database published by the Royal Botanic Gardens, Kew. It was launched in March 2017 with the ultimate aim being "to enable users to access information on all the world's known seed-bearing plants by ...

as of recognizes the following species: The species of this genus can be divided into two main groups, based on their floral structure: One group bears flowers singly or in pairs; the other bears flowers in clusters of between 4 and 20. The species of the second grouping can in turn be divided into two sections: One with purple to dark-brown flowers that are wider than 25mm (e.g. ''

Quaqua mammillaris The genus ''Quaqua'' falls within the tribe of plants known collectively as stapeliads. All stapeliads, including ''Quaqua'', are Old World stem succulents. Species of the genus ''Quaqua'' are exceptionally varied and endemic to southwestern A ...

'' or ''

''); the other with yellow to cream flowers that are narrower than 25mm.P.V.Bruyns (1983). Bradleya 1:63.

References

{{Taxonbar, from=Q7269125 Asclepiadoideae Apocynaceae genera Flora of Southern Africa Taxa named by N. E. Brown