Duvalia (plant)

Duvalia
	Duvalia corderoyi
Systematics
Order :	Enzianartige (Gentianales)
Family :	Dog poison family (Apocynaceae)
Subfamily :	Silk plants (Asclepiadoideae)
Tribe :	Ceropegieae
Sub tribus :	Stapeliinae
Genre :	Duvalia
Scientific name
	Duvalia
	Haw.

Duvalia is a genus of plants in the silk plant family (Asclepiadoideae), which belongs to the Apocynaceae family. The genus is named after the French doctor and botanist Henri Auguste Duval (1777-1814).

features

The Duvalia species are stem, succulent , perennial plants with low, planar growth. The shoots are club-shaped, cylindrical to spherical, square, five or hexagonal in cross section and up to about 10 cm long. They are spotted green, gray-green or reddish. The leaves are very small and triangular.

The flowers, mostly lying flat on the ground, appear successively over a longer period of time near the base of the shoot. The flower stalks are long and glabrous. The hermaphrodite, radial symmetry flowers measure 1 to 5 cm in diameter and are five-fold. The crown is yellow, ocher, brown, red to dark purple. The five corolla lobes are flat or turned up along the median nerve. The staminal and interstaminal side crowns have grown together to form a flat disk. The outer, spindle-shaped, pointed extensions of the staminal secondary crown are curved and point upwards.

The follicles have a length of up to 18 cm and a diameter of up to 1 cm and contain about 40 to 120 seeds. The flat-elliptical, brown seeds have tufts of hair.

Occurrence

The genus Duvalia has a disjoint area and is widespread on the Arabian Peninsula , in northeastern and southern Africa.

Systematics

Illustration of Duvalia angustiloba

Duvalia caespitosa

Duvalia parviflora

Flower of Duvalia parviflora

The genus Duvalia was created by Adrian Hardy Haworth in Syn. Pl. Succ. 44 (1812) validly described. In 1813 a genus of the Fabaceae also received the name Duvalia by Aimé Jacques Alexandre Bonpland in Descr. Pl. Malmaison 130th t. 53 (1813); this name is invalid as a later homonym.

In 1990 Ulrich Meve and Focke Albers divided the genus Duvalia into the two sections Duvalia and Arabica . Meve (In: Albers und Meve) lists 21 species, subspecies and varieties:

Duvalia sect. Duvalia
- Duvalia angustiloba N.E.Br. : Cape Province.
- Duvalia caespitosa (Masson) Haw. : With two varieties:
  - Duvalia caespitosa var. Caespitosa : Cape Province to the Orange Free State .
  - Duvalia caespitosa var. Compacta (Haw.) Meve : Cape Province.
- Duvalia corderoyi (Hook. F.) NEBr. : Cape Province to the Orange Free State .
- Duvalia elegans (Masson) Haw. : Southwest Cape Province.
- Duvalia gracilis Meve : Eastern Cape Province.
- Duvalia immaculata (CALückh.) MBBayer ex LCLeach : Southwestern Cape Province.
- Duvalia maculata N.E.Br. : It occurs from southern Namibia to the Orange Free State .
- Duvalia modesta N.E.Br. : South Eastern Cape Province.
- Duvalia parviflora N.E.Br. : Western Cape Province.
- Duvalia pillansii N.E.Br. : South Eastern Cape Province.
- Duvalia polita N.E.Br. : Southern Tropical Africa and Southern Africa.
- Duvalia pubescens N.E.Br. : It occurs from southwestern Namibia to South Africa.
- Duvalia vestita N.E.Br. : Southern Cape Province.

Duvalia sect. Arabica Meve & F. Albers
- Duvalia eilensis Lavranos : It occurs in eastern Somalia .
- Duvalia galgallensis Lavranos : It occurs in northern Somalia.
- Duvalia sulcata N.E.Br. : With several subspecies:
  - Duvalia sulcata subsp. sulcata : It occurs from north-east Sudan to the south-west Arabian Peninsula.
  - Duvalia sulcata subsp. seminuda (Lavranos) Meve : It occurs in Yemen and Saudi Arabia.
  - Duvalia sulcata subsp. somalensis (Lavranos) Meve : It occurs in Ethiopia, Djibouti , Somalia and Yemen . Some authors also regard it as an independent species: Duvalia somalensis Lavranos .
  - Duvalia sulcata subsp. sudanensis Plowes : The subspecies first described in 2012 occurs in Sudan .
- Duvalia velutina Lavranos : It occurs on the southwestern Arabian Peninsula.

A dubious name is Duvalia anemoniflora (Deflers) RADyer. & Lavranos .

literature

Ulli Meve: Duvalia . In: Focke Albers, Ulli Meve (Hrsg.): Succulents Lexicon Volume 3 Asclepiadaceae (silk plants). Ulmer, Stuttgart 2002, ISBN 978-3-8001-3982-8 , pp. 124-129.
Ulrich Meve, Focke Albers: The species concept in Duvalia (Asclepiadaceae): A preliminary revision of the genus In: Mitteilungen aus dem Institut für Allgemeine Botanik in Hamburg . Volume 23, 1990, pp. 595-604.

Individual evidence

↑ Lotte Burkhardt: Directory of eponymous plant names . Extended Edition. Botanic Garden and Botanical Museum Berlin, Free University Berlin Berlin 2018. [1]
↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u Rafaël Govaerts (ed.): Duvalia - World Checklist of Selected Plant Families des Royal Botanic Gardens, Kew. Last accessed on November 12, 2018.

Web links

Commons : Duvalia - collection of images, videos and audio files

The genus Duvalia at GRIN
Sigrid Liede-Schumann & Ulrich Meve: The Genera of Asclepiadoideae, Secamonoideae and Periplocoideae (Apocynaceae) : Genus Duvalia - Online.
Martin Heigan: Stapeliad's "Hidden Treasures of the Desert" .
Friederike Hübner: Asclepidarium - Asclepiadaceen and more .

[Burkhardt2018-1] Lotte Burkhardt: Directory of eponymous plant names . Extended Edition. Botanic Garden and Botanical Museum Berlin, Free University Berlin Berlin 2018. [1]

[WCSP-2] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u Rafaël Govaerts (ed.): Duvalia - World Checklist of Selected Plant Families des Royal Botanic Gardens, Kew. Last accessed on November 12, 2018.