Micromyrtus

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Micromyrtus
Micromyrtus blakelyi at its natural site in Muogamarra Nature Reserve, New South Wales, Australia

Micromyrtus blakelyi at its natural site in Muogamarra Nature Reserve, New South Wales , Australia

Systematics
Eurosiden II
Order : Myrtle-like (Myrtales)
Family : Myrtle family (Myrtaceae)
Subfamily : Myrtoideae
Tribe : Chamelaucieae
Genre : Micromyrtus
Scientific name
Micromyrtus
Benth.

Micromyrtus is a genus of plants withinthe myrtle family (Myrtaceae). All up to 44 species are originally only found in Australia and are called "Heath myrtles" there.

description

Appearance and leaves

Micromyrtus species grow as spreading to upright, evergreen shrubs that usually reach heights of 0.4 to 1 (0.3 to 2) meters. They contain essential oils . The above-ground parts of the plant are bare.

The opposite (or cross-opposite) leaves on the branches are at most short-stalked or sessile. The herbaceous or leathery, simple, relatively small leaf blades are dotted with glands (particularly good view of the underside of the leaves) and have an aromatic smell. There are no stipules .

Inflorescences, flowers and pollination

The reduced inflorescences usually contain only one, rarely two or three flowers at most over very short inflorescence shafts in the leaf axils in the upper area of ​​the branches. Each flower stands over a pair of durable or rapidly perishable bracts .

The relatively small, hermaphrodite flowers are mostly radial symmetry and usually five, rarely six-fold with a double flower envelope . The flower cup (hypanthium) that has grown together with the ovary is ribbed or grained. The five or rarely six free, small sepals are membranous or corolla-like with a smooth or fringed edge. The five or rarely six free petals are entire, elliptical, egg or circular and can be nailed. The colors of the petals are yellow or white to pink. The stamens are usually straight in the bud or rarely curved a few inward. Usually five or six more or less identical stamens are arranged in one or two circles . The stamens are all fertile. The thread-like or belt-shaped stamens are free from each other and not fused with the petals. The look-alike dust bag open with longitudinal slots and do not project beyond the petals. There is a discus. Two carpels are one under permanent, single-chamber ovary grown. Two or ten anatropic ovules are arranged in basal to lateral placentation . The stylus ends in a simple scar that does not protrude over the bracts.

The pollination is done by insects ( Entomophilie ) or birds ( ornithophily ).

Fruits and seeds

The dry closing fruits are mostly single-seeded, rarely two- to three-seeded nut fruits . The ellipsoidal to kidney-shaped seeds contain a curved embryo with two cotyledons ( cotyledons ) and there is no endosperm present.

Chromosome number

The basic chromosome number is n = 11. In some species there is diploidy , i.e. 2n = 22; but tetraploidy was also found.

Spread and endangerment

The genus Micromyrtus is distributed with up to 44 species in southern, central and northeastern Australia . Species occur in the Australian states of Western Australia , South Australia , Queensland , New South Wales , Victoria and in the Northern Territory and Australian Capital Territory .

Micromyrtus grandis is rated as "Endangered" = "highly endangered". Micromyrtus blakelyi and Micromyrtus minutiflora are classified as "Vulnerable" = "endangered".

Systematics

The genus Micromyrtus was established in 1865 by George Bentham in G. Bentham & JDHooker: Genera Plantarum , 1, p. 700. Lectotype species is Micromyrtus drummondii Benth. nom. superfl., today this is a synonym of Micromyrtus obovata (Turcz.) JWGreen . The generic name Micromyrtus is made up of the Greek word micro for "small" and myrtus , a genus from the Myrtaceae family. The last partial revision of the genus Micromyrtus took place in BL Rye: A partial revision of the south-western Australian species of Micromyrtus (Myrtaceae: Chamelaucieae) , In: Nuytsia , Volume 16, Issue 1, 2006, pp. 121-122.

The genus Micromyrtus belongs to the tribe Chamelaucieae in the subfamily Myrtoideae within the family of Myrtaceae .

Branch with leaves and flowers of Micromyrtus ciliata
Branch with leaves and flowers of Micromyrtus leptocalyx
Branch with leaves and flowers of Micromyrtus minutiflora

There are up to 44 Micromyrtus species:

swell

Individual evidence

  1. ↑ a b c d e Entry in Australian Plant Name Index = APNI. last accessed on January 19, 2013
  2. ↑ a b c d e f g h i j k l JW Green: Entry in the Electronic Flora of South Australia genus Fact Sheet . last accessed on January 19, 2013
  3. ↑ a b c d e f g h Peter G. Wilson: Entry in the New South Wales Flora Online . last accessed on January 19, 2013
  4. ↑ a b c d e f g h i j k l m n o p q r s t u HR Coleman: Entry in the Western Australian Flora , last change 2008. Last accessed on January 19, 2013
  5. ↑ IPCN Chromosome Reports . last accessed on January 19, 2013
  6. ↑ EPBC Act List of Threatened Flora . last accessed on January 19, 2013
  7. ↑ First publication scanned at biodiversitylibrary.org .
  8. ↑ Micromyrtus at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed January 19, 2013.
  9. ↑ Micromyrtus in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved January 19, 2013.
  10. ↑ Rafaël Govaerts (ed.): Micromyrtus. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved April 30, 2020. (last changes adapted from R. Govaerts, N. Sobral, P. Ashton, F. Barrie, BK Holst, LL Landrum, K. Matsumoto, F. Fernanda Mazine, E. Nic Lughadha, C. Proença & al .: World Checklist of Myrtaceae , Kew Publishing, Royal Botanic Gardens, Kew, 2008, pp. 1-455.)

Web links

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

Supplementary literature

  • JW Green: Thryptomene and Micromyrtus (Myrtaceae) in arid and semi-arid Australia. In: Nuytsia , Volume 3, Issue 2, 1980, pp. 183-205: PDF .