Gaussia (genus)

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Gaussia
Gaussia maya

Gaussia maya

Systematics
Class : Bedecktsamer (Magnoliopsida)
Monocots
Commelinids
Order : Palm- like arecales
Family : Palm family (Arecaceae)
Genre : Gaussia
Scientific name
Gaussia
H. Wendl.

Gaussia is a genus of palm found in America. It is named after the German mathematician Carl Friedrich Gauß .

features

The representatives are single-stemmed, medium-sized to large, monoecious , unreinforced palms with pinnate leaves. They bloom several times. The trunk brown or gray to whitish, straight or sometimes swollen at the base or in the middle. The leaf scars are clear and broad, or inconspicuous. The roots carry small spiky side roots that form a conspicuous structure at the base of the trunk.

The chromosome number is 2n = 28.

leaves

The leaves are pinnate. The leaf sheaths are wide at the base and narrow distal to the petiole . When ripe, they tear open opposite the leaf stalk. The leaf sheaths do not form a clear crown shaft. The stem is short and furrowed only slightly and narrowly at the top. The rachis is clearly angular on the top and rounded on the underside. The leaflets are pointed and simply folded. They are broadly duplicated at the point of attachment. They are lightly covered with wax. The midrib is prominent with two or more prominent pairs of lateral nerves.

Inflorescences

Several inflorescences are often formed on one stem at the same time. The inflorescences are between the leaves (interfoliar) and do not last long. They fall off simultaneously with or shortly after the leaves that carry them. An inflorescence is branched two to three times. The peduncle is long and ascending. The cover sheet is very short, tubular, flat and almost two-keeled. It is pointed and open at the end. There are four to seven bracts on the peduncle, each longer than the previous one. They are roehrig, the last reaching over towering over the base of the first flower-bearing side branches. The inflorescence axis is about the same length as the stem. The side axes of the first order are numerous, compact and arranged in a spiral. The flower-bearing axes (rachillae) are glabrous, slender and have no bracts. On them are rows of flowers ( coils ) in a spiral . These coils consist of a proximal female flower and three to seven (rarely only two) distal male flowers. The distal flower opens first, the female usually opens when all the male ones have already faded. All flowers are shed unless they are fertilized.

blossoms

The flowers are small, green at the bud stage and yellow to yellow-green at flowering.

The male flowers are ovate to ellipsoidal in the bud stage. The three sepals are rounded and imbricat at the base . The three petals are valvate , fleshy or thin, and not clearly annoyed when developed. In the bud stage they are clearly annoyed (when dry). The six stamens have very short or clearly developed filaments that are not bent inwards in the bud. The anthers are dorsifix, deeply arrow-shaped or bilobed at the base and slightly bilobed above. The rudiment of the pistil is angular-columnar and in the bud as long as the stamens. The pollen is ellipsoidal and slightly asymmetrical. The germ opening is a distal sulcus.

The female flowers are egg-shaped. The three sepals are free, rounded and imbricat at the base. The three petals are narrowly imbricated at the base and subvalvate to valvate above. The tips protrude apart to bloom. There are six small, tooth-like staminodes . The gynoeceum is angular-egg-shaped and has three scars curved back . It consists of three fruit compartments, each with an ovule . The ovules sit laterally and are campylotropic.

Part of a fruit cluster of Gaussia maya

Fruits and seeds

The fruits are ellipsoidal, spherical or kidney-shaped, and red or deep orange in color. They are fleshy and have scar remains at the base. The exocarp is smooth, the mesocarp has no anastomosing fibers towards the endocarp . The seed is ellipsoidal to kidney-shaped or almost spherical. It is not connected to the endocarp and has a pedunculated or undetectable, round basal hilum. The raphe is inconspicuous, there are few, hardly branched raphen branches. These rise asaxially, bend sideways and descend abaxially towards the embryo. The endosperm is homogeneous, the embryo sits on the side.

Distribution and locations

Gaussia is restricted to Central America and the Caribbean . It occurs in Mexico , Guatemala , Belize , Cuba , Hispaniola and Puerto Rico . It usually grows on limestone hills ( mogotes ). The palm trees can grow from crevices in steep rocks, on steep slopes or on low hills. They often grow on the pyramids in Guatemala. They are less common in high forests over limestone.

Gaussia attenuata
Gaussia princeps

Systematics and distribution

The genus Gaussia was established in 1865 by Hermann Wendland . The generic name Gaussia honors the German mathematician Carl Friedrich Gauß (1777–1855). Synonyms for Gaussia H.Wendl. are: Aeria O.F.Cook , Opsiandra O.F.Cook .

The genus Gaussia is placed within the family Arecaceae in the subfamily Arecoideae , tribe Chamaedoreeae . The genus is monophyletic . The relationships between Gaussia and the tribe are not clear.

The Royal Botanic Gardens, Kew's World Checklist of Selected Plant Families recognizes the following species:

literature

  • John Dransfield, Natalie W. Uhl, Conny B. Asmussen, William J. Baker, Madeline M. Harley, Carl E. Lewis: Genera Palmarum. The Evolution and Classification of Palms. Second edition, Royal Botanic Gardens, Kew 2008, ISBN 978-1-84246-182-2 , pp. 381-383.

Individual evidence

  1. ↑ a b c d e f g Rafaël Govaerts (Ed.): Gaussia. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved August 4, 2018.

Web links

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