Ixora

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Ixora
Variety of Ixora coccinea

Variety of Ixora coccinea

Systematics
Euasterids I
Order : Enzianartige (Gentianales)
Family : Red family (Rubiaceae)
Subfamily : Ixoroideae
Tribe : Ixoreae
Genre : Ixora
Scientific name of the  tribe
Ixoreae
A.Gray
Scientific name of the  genus
Ixora
L.

Ixora is the only genus of the tribe Ixoreae within the plant family of the Rubiaceae (Rubiaceae). The 500 to 560 species are mainly found in tropical areas in Africa , Madagascar , Asia , on Pacific islands and in the Neotropics .

description

Trunk with bark of Ixora pavetta
Illustration of Ixora umbellata
Kauliflore flowers of Ixora margaretae
Ripe fruits of Ixora coccinea
Butterfly on inflorescence of Ixora casei

Appearance and leaves

Ixora species are evergreen, woody plants that grow as shrubs or small trees . The unreinforced shoot axes are mostly independently upright and only rarely climb ( Ixora hekouensis ).

The leaves, which are mostly opposite or rarely in threes in whorls, are divided into a petiole and a leaf blade. They do not have domatia . The base of the petioles is articulated. The simple leaf blades are shiny, glabrous, and often leathery. The durable until early sloping side leaves are triangular, short fused with acute or begranntem upper end and they can shoot around the axis.

Inflorescences and flowers

On the main stem, zymose or umbrella-like inflorescences that contain a few to many flowers are formed at the end of the stem or sometimes on reduced, leafless side branches . There may be inflorescence stems. The inflorescence axes are often articulated. Cauliflora is present in some species (for example Ixora cauliflora , Ixora margaretae ). The bracts and bracts are reduced; if cover sheets are present, then they are often fused in pairs. There may be flower stalks.

The often fragrant, hermaphrodite flowers are zygomorphic and usually four, rarely five-fold with a double flower envelope . The mostly four, rarely five sepals are fused and the calyx ends truncated or with recognizable calyx teeth. The petals are often white to whitish, yellow to orange and red to pink, they often turn reddish when drying. The mostly four, rarely five up to nine petals are fused together like a saucer; The long, slender corolla tube is bald inside or hairy on the throat. The corolla lobes overlap convolutely in the flower bud and spread out during the anthesis. There are usually four, rarely five stamens ; they are about the same length as the crown or they tower above it. The short or reduced stamens are inserted at the throat of the crown. The disc is thick or thickened. The two-chamber ovary contains only one hanging in each chamber ovule . The thread-like stylus is spindle-shaped to club-shaped in the upper area and usually ends in two linear, back-curved scars that (slightly) protrude over the crown.

Fruits and seeds

The almost spherical to ellipsoidal or egg-shaped drupes are covered by the durable sepals and are leathery or fleshy. The black or red drupes when ripe usually contain two stone pits with one seed each. The stone cores are plano-convex or concavo-concave and have a leathery or parchment-like shell. The seeds are medium in size, ellipsoidal to oblanceolate with a membranous seed coat and a cartilaginous endosperm .

Sets of chromosomes

The basic chromosome number is x = 11, the species examined have diploidy , i.e. 2n = 22.

Habit, leaves and inflorescences of Ixora brachiata
Ixora casei leaves and inflorescences
Ixora chinensis
Ixora elongata leaves and inflorescences
Ripe fruits of Ixora elongata
Ixora finlaysoniana leaves and inflorescence
Ixora grandifolia
Ixora javanica inflorescence
Habit, leaves and inflorescences of Ixora lobbii
Unripe fruits of Ixora malabarica
Habit, leaves and inflorescences of Ixora malabarica
Ixora muelleri
Ixora nigricans
Ixora pavetta
Ixora polyantha
Ixora polyantha leaves and inflorescence
Ixora rosae inflorescence
Ixora siamensis leaves and inflorescence

Systematics and distribution

The genus Ixora was set up in Species Plantarum , 1st edition, p. 110 in 1753 . As Lectotypusart was Ixora coccinea L. by Albert Spear Hitchcock in proposals by British Botanists , 1929, determined S. 124th Synonyms for Ixora L. are: Schetti Adans. , Sideroxyloides Jacq. , Patabea Aubl. , Myonima Comm. ex A.Juss. , Siderodendrum Schreb. , Bemsetia Raf. , Panchezia Montrouz. , Charpentiera Vieill. , Hitoa Nadeaud , Versteegia Valeton , Becheria Ridl. , Thouarsiora Homolle ex Arènes , Captaincookia N.Hallé , Doricera Verdc. , Tsiangia But, HHHsue & PTLi .

Ixora is the only genus of the tribe Ixoreae in the subfamily Ixoroideae within the family of Rubiaceae . Molecular genetic studies show that the genus Ixora contains all the most closely related earlier genera to a very large extent.

The genus Ixora is widespread mainly in tropical areas in Africa , Madagascar , Asia , in the Neotropics and on Pacific islands. There are 18 species in China, 9 of them only there.

The genus Ixora now contains 500 to 564 (previously 300 to 400) species:

A variety of Ixora × williamsii used as an ornamental plant

use

Varieties of some species (especially Ixora coccinea ) are used as ornamental plants .

swell

Individual evidence

  1. ↑ a b c d e Tao Chen & Charlotte M. Taylor: Ixora , p. 177 - the same text online as the printed work , In: Flora of China Editorial Committee: Wu Zheng-yi, Peter H. Raven & Deyuan Hong (eds.) : Flora of China , Volume 19 - Cucurbitaceae through Valerianaceae, with Annonaceae and Berberidaceae , Science Press and Missouri Botanical Garden Press, Beijing and St. Louis, February 28, 2011. ISBN 978-1-935641-04-9
  2. ↑ a b c d e S. Nazimuddin & Mohammad Qaiser: Flora of Pakistan , Volume 190, Rubiaceae. University of Karachi, Department of Botany, Karachi, 1989: Ixora online at Tropicos.org at the Missouri Botanical Garden.
  3. ^ Entry in the IPCN Chromosome Reports at Tropicos.org of the Missouri Botanical Garden.
  4. ↑ First publication scanned at biodiversitylibrary.org .
  5. ^ Ixora at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed December 27, 2013.
  6. ↑ a b Rafaël Govaerts (Ed.): Ixora. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved November 2, 2018.
  7. ^ A b Ixora in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved December 27, 2013.
  8. ↑ a b Arnaud Mouly, Sylvain G. Razafimandimbison, Jacques Florence, Joël Jérémie & Birgitta Bremer: Paraphyly of Ixora and New Tribal Delimitation of Ixoreae (Rubiaceae): Inference from Combined Chloroplast (rps16, rbcL, and trnT-F) Sequence Data , In: Annals of the Missouri Botanical Garden. Volume 96, Issue 1, 2009, pp. 146-160: doi : 10.3417 / 2006194
  9. ↑ a b Arnaud Mouly, Sylvain G. Razafimandimbison, Anbar Khodabandeh & Birgitta Bremer: Phylogeny and classification of the species-rich pantropical showy genus Ixora (Rubiaceae-Ixoreae) with indications of geographical monophyletic units and hybrids , In: American Journal of Botany , Volume 96, Issue 3, 2009, pp. 686-706: doi : 10.3732 / ajb.0800235

Web links

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