Macrozamia macdonnellii
| Macrozamia macdonnellii | ||||||||||||
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Macrozamia macdonnellii with infructescence in Stanley Chasm in the MacDonnell Ranges |
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| Scientific name | ||||||||||||
| Macrozamia macdonnellii | ||||||||||||
| ( F.Muell. Ex Miq. ) A.DC. |
Macrozamia macdonnellii is a species of the genus Macrozamia within the order of the cycads (Cycadales). The specific epithet (and also the English common name MacDonnell Ranges Cycad ) refers to the area of origin, the MacDonnell Ranges .
description
Vegetative characteristics
The tree-shaped Macrozamia macdonnellii forms an above-ground, mostly short trunk, which reaches heights of 0.4 to rarely 3 m and a diameter of 60 to 80 cm. The trunk grows very slowly, growth is around 1 cm per year in large plants.
Macrozamia macdonnellii forms a crown of 50 to 120 leaves . The 12 to 25 cm long-stalked, dull bluish-leaves, with the bent back rachis bent stiff down a length of up to 1.5 m to 2.2 reach keeled are weak and easy feathered. A pinnate foliage has 120 to 170 leaflets . The pointed leaflets are straight, slightly runny with a smooth edge; the lowest are reduced to thorns, followed by about 15 to 25 mm wide and the middle ones are 20 to 30 cm long and 0.7 to 1.1 cm wide.
Generative characteristics
The male cones are slender with a length of 25 to 40 cm and a diameter of 8 to 10 cm; they end with a 0 to 25 mm long spine and have 3 to 4 cm long and 1.5 to 2 cm wide microsporophylls .
The female cones have a length of 40 to 50 cm and a diameter of 20 to 27 cm; they end with a 0 to 2 mm long spine and have 7 to 10 cm long megasporophylls with a shield-shaped end that is 8 to 12.5 cm wide and 4 to 6 cm high.
The numerous, with a length of 6 to 8 cm and a diameter of 4 to 5.3 cm, egg-shaped seeds are surrounded by an intense orange to orange-brown sarcotesta .
Occurrence
Macrozamia macdonnellii occurs exclusively in Central Australia in the Northern Territory endemically in the mountains of the Macdonnell Ranges and some adjacent mountain ranges. There it usually grows in or in the area of the deep, partially shady gorges, on slopes in open stands of trees or occurs in areas overgrown with spiked grass.
Macrozamia macdonnellii is the only one of the genus Macrozamia that occurs in Central Australia.
Danger
Macrozamia macdonnellii is not considered to be endangered in its existence. It is listed in Appendix II of the Washington Convention on Species Protection (CITES).
Systematics
The first description was under the name "Macdonelli" as Encephalartos macdonnellii Ferdinand von Mueller in Friedrich Anton Wilhelm Miquel : Verslagen en mededeelingen der Koninklijke Akademie van Wetenschappen. 15, p. 376, as (1863). In 1868 Alphonse Pyrame de Candolle presented it in Prodromus Systematis Naturalis Regni Vegetabilis , Volume 16 (2), p. 537 under the name Macrozamia macdonnellii (F.Muell. Ex Miq.) A.DC. into the genus Macrozamia .
swell
- Ken Hill: Macrozamia macdonnellii - Entry on The Cycad Pages .
Web links
- C. Nano & CR Pavey: National Recovery Plan For The MacDonnell Ranges Cycad Macrozamia macdonnellii : PDF-Online from Department of Natural Resources, Environment, The Arts and Sport, Northern Territory , 2008.
- Macrozamia macdonnellii inthe IUCN Red List of Threatened Species 2013.2. Listed by: Hill, KD, 2009. Retrieved April 28, 2014.