Quaqua
Quaqua mammillaris (the "aroena"), a widespread and common species from the south-western Cape.
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Asterids
Order:	Gentianales
Family:	Apocynaceae
Subfamily:	Asclepiadoideae
Tribe:	Ceropegieae
Genus:	Quaqua N.E.Br.

The genus Quaqua falls within the tribe of plants known collectively as stapeliads. All stapeliads, including Quaqua, are Old World stem succulents.^[1]

Species of the genus Quaqua are exceptionally varied and endemic to southwestern Africa, and locally very common in Namaqualand.

Description

Species of Quaqua are usually characterised by having stout, firm, 4 or 5-sided stems bearing conical tubercles which often have a tough, tapering spike at their ends. A few species lack the spikes or have smoothly rounded tubercles.^[1]

Quaqua flowers are distinctive from those of other southern African stapeliads for their numerous inflorescences 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 or lemon), 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, and usually have a repulsive odor of urine or excrement. These species are pollinated by flies.^[1]

• 
  Quaqua pillansii, from the Little Karoo, has smooth, erect grey stems
• 
  Quaqua ramosa, 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 & Namibia. Its distribution closely mirrors that of related genus Tromotriche.

Species

Plants of the World Online as of As of January 2023^[update] recognizes the following species:^[2]

Image	Scientific name	Distribution
	Quaqua acutiloba (N.E.Br.) Bruyns	South Africa and Namibia.
	Quaqua albersii Plowes	South Africa (Vredendal)
	Quaqua arenicola (N.E.Br.) Plowes	South Africa (Cape Province)
	Quaqua arida (Masson) Plowes	South Africa (Cape Province)
	Quaqua armata (N.E.Br.) Bruyns	South Africa (Cape Province)
	Quaqua aurea (C.A.Lückh.) Plowes	South Africa (Cape Province)
	Quaqua bayeriana (Bruyns) Plowes	South Africa (Cape Province)
	Quaqua cincta (C.A.Lückh.) Bruyns	South Africa (Cape Province)
	Quaqua framesii (Pillans) Bruyns	South Africa (Cape Province)
	Quaqua incarnata (L.f.) Bruyns	South Africa and Namibia.
	Quaqua inversa (N.E.Br.) Bruyns	South Africa (Cape Province)
	Quaqua linearis (N.E.Br.) Bruyns	South Africa (Cape Province)
	Quaqua mammillaris (L.) Bruyns	South Africa and Namibia.
	Quaqua multiflora (R.A.Dyer) Bruyns	South Africa (Cape Province)
	Quaqua pallens Bruyns	South Africa (Cape Province)
	Quaqua parviflora (Masson) Bruyns	South Africa (Cape Province)
	Quaqua pillansii (N.E.Br.) Bruyns	South Africa (Cape Province)
	Quaqua pruinosa (Masson) Bruyns	South Africa (Cape Province)
	Quaqua pulchra (Bruyns) Plowes	South Africa (Cape Province)
	Quaqua ramosa (Masson) Bruyns	South Africa (Cape Province)

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 or Quaqua pillansii); the other with yellow to cream flowers that are narrower than 25mm.^[3]