Xenostegia

Xenostegia
	Xenostegia tridentata
Systematics
	Nuclear eudicotyledons
	Asterids
	Euasterids I
Order :	Nightshade (Solanales)
Family :	Bindweed family (Convolvulaceae)
Genre :	Xenostegia
Scientific name
	Xenostegia
	DFAustin & Staples

Xenostegia is a plant genus in the family of wind plants (Convolvulaceae). The only five species are common in the Paleotropic .

description

Illustration from Botanical Magazine Volume 90, 1864 from Xenostegia tridentata

Vegetative characteristics

Xenostegia species are perennial , herbaceous plants that grow prostrate or more or less twisting at the tips.

The alternate leaves are arranged in a petiole and a leaf blade . The simple leaf blades are linear, elongated-linear, lanceolate-linear or inverted-lanceolate to spatulate. The base of the blades is more or less spear-shaped, and the resulting lobes easily embrace the stems. The leaf margin is serrated or entire, the tip is pointed, curved or provided with three teeth.

Generative characteristics

The lateral inflorescences are cymes of one to three flowers .

The hermaphroditic flowers are radial symmetry and five-fold with a double flower envelope . The five sepals are elongated or elongated-ovoid, more or less the same shape or shape, pointed or blunt. The inner three sepals are somewhat narrower and taper at the tip into narrow points. All sepals enlarge until the fruit is ripe. The crown is broadly funnel-shaped or bell-shaped, pale yellow or whitish, often with a purple center. The anthers are not twisted after opening, the pollen grains are spherical, pantoporate and not prickly. The stamp is not above the crown beyond the ovary is zweikammerig and forms four ovules . The thread-like stylus ends in a two-spherical scar .

The four-lobed capsule fruits are hairless or hairy at the tip and contain one to four seeds. The brownish to black seeds are egg-shaped, three-sided.

Xenostegia tridentata subsp. hastata

Systematics and distribution

The genus Xenostegia was established in 1981 by Daniel Frank Austin and George Staples . Type species is Xenostegia tridentata (L.) DFAustin & Staples .

Within the family Convolvulaceae , the genus Xenostegia is classified according to molecular biological knowledge in the tribe Merremieae, which has been provisionally established.

The genus Xenostegia is common in the tropical and subtropical areas of Asia , Africa and Australia .

The genus Xenostegia includes only five species:

Xenostegia alatipes (Dammer) ARSimões & Staples (Syn .: Xenostegia tridentata subsp. Alatipes (Dammer) Lejoly & Lisowski ): It occurs from Kenya to southern tropical Africa.
Xenostegia medium (L.) DFAustin & Staples : The distribution area extends from Tanzania to Mozambique , Madagascar and the Comoros .
Xenostegia pinnata (Hochst. Ex Choisy) ARSimões & Staples : It occurs in tropical and southern Africa.
Xenostegia sapinii (De Wild.) ARSimões & Staples : It occurs in Congo and in the Democratic Republic of the Congo.
Xenostegia tridentata (L.) DFAustin & Staples : The three subspecies are common in the tropics and subtropics of the Old World .:
- Xenostegia tridentata subsp. angustifolia (Jacq.) Lejoly & Lisowski : It occurs in tropical and southern Africa.
- Xenostegia tridentata subsp. hastata (Ooststr.) Parmar : It occurs from China to tropical Asia and on Palau .
- Xenostegia tridentata subsp. tridentata : It occurs from northeastern tropical Africa to the Arabian Peninsula, in Angola , Madagascar and on the Comoros and from tropical and subtropical Asia to the Carolines .

swell

literature

Fang Rhui-cheng, George Staples: Convolvulaceae. : Xenostegia. , P. 300 In: Wu Zheng-yi, Peter H. Raven (Ed.): Flora of China . Volume 16: Gentianaceae through Boraginaceae . Science Press / Missouri Botanical Garden Press, Beijing / St. Louis 1995, ISBN 0-915279-33-9 (English).

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k Rafaël Govaerts (Ed.): Xenostegia. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved November 24, 2018.
^ Saša Stefanović, Daniel Austin, Robert Olmstead: Classification of Convolvulaceae: A Phylogenetic Approach. In: Systematic Botany , Volume 28, Number 4, 2003, pages 791-806. doi : 10.1043 / 02-45.1 (currently unavailable) ( online )

Web links

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

[WCSP-1] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k Rafaël Govaerts (Ed.): Xenostegia. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved November 24, 2018.

[Stefanovic03-2] Saša Stefanović, Daniel Austin, Robert Olmstead: Classification of Convolvulaceae: A Phylogenetic Approach. In: Systematic Botany , Volume 28, Number 4, 2003, pages 791-806. doi : 10.1043 / 02-45.1 (currently unavailable) ( online )