Hemp palms
| Hemp palms | ||||||||||||
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Chinese hemp palm ( Trachycarpus fortunei ) |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Trachycarpus | ||||||||||||
| H. Wendl. |
The hemp palms ( Trachycarpus ) are a genus of palms native to Asia . Some species of these fan palms are popular ornamental plants.
features
The representatives are moderately large to small palms, which usually grow solitary, rarely clump-shaped. They are stemless or upright, unreinforced or lightly reinforced, as well as flowering several times, diocesan or polygamous. The trunk is prostrate or upright. It becomes bald over time and is covered with conspicuous, rather densely seated leaf scars, or it is covered with the perennial stalk bases and fibrous sheaths, or it is covered by a dress of dead leaves.
The chromosome number is 2n = 36.
leaves
The leaves are fan-shaped , folded induplicately and remain on the plant after they have died (marzescence). The leaf sheaths disintegrate into a mass of fine to coarse fibers, the upper edge is ribbon-like and twisted. The petiole is long, narrow, flat or slightly rounded on the top, rounded or angular on the underside. The stalk is a scattered, sloping hairs or is glabrous. At the edges it has very fine teeth or is not reinforced. The adaxial hastula is clearly formed, rounded or triangular; the abaxial hastula is absent. The leaf blade is fan-shaped to almost circular. It is divided equally or unequally along the adaxial ribs into simply folded segments. These are shallow in two parts (bifid) at the top.
Inflorescences
The inflorescences stand individually between the leaves (interfoliar). They are curved or more upright. They are rich and branched up to four times. The peduncle is oval in cross section and has sparse hair. The cover sheet is complete, conspicuous, with a tubular base, is inflated distally, bilaterally double-keeled, tears at the tip and along one side, and is covered with a decrepit indument. There are one to three bracts on the inflorescence axis, which are similar to the previous leaf, but are single-keeled. The inflorescence axis is shorter or longer than the stalk and has bracts in a spiral arrangement that resemble those on the stalk, but each has a side branch of the first order. The bracts on the lateral axes are inconspicuous, triangular, not divorced. The flower-bearing axes (rachillae) are slender, stiff, short, crowded, bright yellow to greenish in color, glabrous to slightly hairy. On them are the flowers in a spiral arrangement, which stand individually or in groups of two to three flowers. They are sitting or standing on low tubercles. Each flower has a small, membranous bractole .
blossoms
The flowers of both sexes are similar to each other. The three sepals are connected at the base, triangular, short or long and glabrous. The three petals are usually much longer than the calyx, they are free, imbricat , oval with a triangular tip or rounded, and glabrous. The six stamens have free, fleshy filaments. The anthers are short, oblong, sometimes slightly pointed and latrors. When staminodes are found in female flowers , they resemble fertile stamens, but have flat filaments and empty anthers.
The three carpels are free, not overgrown, hairy, with partially open abdominal seam. The stylus is very short. The ovule sits basal and is hemianatropic. It is surrounded dorsally and ventrally by a fleshy aril . Pistillodes , if present, are similar to the fertile carpels, only significantly smaller.
The pollen is ellipsoidal with slight to distinct asymmetry. The germ opening is a distal sulcus. The longest axis measures 22 to 32 microns.
Fruits and seeds
The fruit usually develops from one of the three carpels. It is purple-black, kidney-shaped to oblong, slightly furrowed on the adaxial side, the remains of the scars are laterally or subapical. The exocarp is thin, hairy in the unripe fruit, then glabrous in the ripe one. The mesocarp is thin and interspersed with a layer of tannic cells. The endocarp is crusty. The seed is kidney-shaped to oblong, the endosperm is homogeneous, and has a shallow to deep lateral indentation of the seed coat. The embryo sits laterally.
Distribution and locations
The distribution area of the genus extends from the Himalayas in northern India through northern Thailand to Vietnam and China . Trachycarpus oreophilus occurs up to 2400 m above sea level. Also Trachycarpus takil comes in damp oak forests prior to 2400 meters above sea level, where the ground from November to March is snowy. Trachycarpus fortunei is one of the coldest cultivated palm trees and is hardy on the British Isles and partly in southwest Germany . In the milder regions of Switzerland, originally exposed as an ornamental plant, it is already one of the invasive plants because it is a threat to native woody plants . A study published in 2019 found some small occurrences in Austria .
Systematics
The genus Trachycarpus H. Wendl. is placed within the family Arecaceae in the subfamily Coryphoideae , Tribus Trachycarpeae , Subtribus Rhapidinae . The genus is likely monophyletic . The relationship to the other genera of the subtribes is still unclear.
In the World Checklist of Selected Plant Families of the Royal Botanic Gardens, Kew , the following types are recognized:
- Chinese hemp palm ( Trachycarpus fortunei (Hook.) H. Wendl .; Syn .: Trachycarpus wagnerianus Becc. ): The home is China and Myanmar.
- Trachycarpus geminisectus Spanner, Gibbons, VD Nguyen & TP Anh : The home is northern Vietnam. It was first described in 2003.
- Trachycarpus latisectus Spanner, Noltie & Gibbons : The home is the Darjiling district in the state of West Bengal in India.
- Trachycarpus martianus (Wall. Ex Mart.) H. Wendl. : The home is the Himalayas to China.
- Trachycarpus nanus Becc. : The home is Yunnan .
- Trachycarpus oreophilus Gibbons & Spanner : The home is northern Thailand.
- Trachycarpus princeps Gibbons, Spanner & San Y.Chen : The home is southwestern Yunnan .
- Trachycarpus ravenii Aver. & KSNguyen : It wasfirst describedfrom Laos in 2014.
- Trachycarpus takil Becc. : The homeland is the Himalayas.
- Trachycarpus ukhrulensis M.Lorek & KCPradhan : The home is Manipur in eastern India.
Trachycarpus was first described by Hermann Wendland , the publication bears the year 1861, but was probably not published until 1863. Type species (lectotype) is Trachycarpus fortunei . The generic name is derived from the ancient Greek words trachus = rough and karpos = fruit and refers to the irregularly shaped fruits.
use
The trunks are used as posts in China, the fibers of the leaf sheaths and trunk are made into brushes and raincoats. Seeds are used medicinally and are believed to have cancer-curing effects.
In Central Europe the Chinese hemp palm is used as an ornamental plant. It spreads invasively mainly on the southern side of the Alps, such as in Ticino, Switzerland, which is why it is also called the Ticino palm.In Germany, wild occurrences are only possible in areas with extremely mild winters, such as in the Rhineland.
supporting documents
- 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. 251-253.
Individual evidence
- ↑ The national data and information center for the Swiss flora: Hemp palm
- ↑ Climate change is causing palm trees to sprout in Austria
- ↑ Rafaël Govaerts (Ed.): Trachycarpus. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved May 13, 2012.
- ↑ The national data and information center for the Swiss flora: Hemp palm
