Buckthorn
| Buckthorn | ||||||||||||
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Holly buckthorn ( Rhamnus alaternus ) |
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| Scientific name | ||||||||||||
| Rhamnus | ||||||||||||
| L. |
Buckthorn ( Rhamnus ), also known as thorn ways, forms a genus within the family of the cross thorn plants (Rhamnaceae). The approximately 100 species are distributed worldwide except for a few regions.
Description and ecology
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Vegetative characteristics
The Rhamnus species are mostly deciduous, rarely evergreen shrubs and small trees . They often form thorns . Some species form bud scales on the winter buds .
The opposite or change-constant , often in clusters on short shoots arranged leaves are divided into petiole and leaf blade. The leaf blades are simple and often serrate. The stipules are sharply pointed.
Generative characteristics
The flowers are solitary or in zymose , racemose or paniculate inflorescences .
The inconspicuous flowers are often hermaphroditic and four or five-fold with a double flower envelope . The flower color is greenish-white or yellowish. The four or five sepals are fused bell-shaped to cup-shaped, and the calyx ends in egg-shaped-triangular calyx tips. The four to five petals are shorter than the sepals, rarely they are completely absent. The four to five stamens have dorsally fixed anthers. The spherical, free-standing ovaries are above.
The leathery or fleshy, berry-like stone fruits contain two to four kernels that are spread by birds. The fruits of most species contain a yellow dye, the seeds abundant protein and oils.
Systematics and distribution
The Rhamnus species are mostly found in temperate to tropical areas of the northern hemisphere , mainly in East Asia and North America , and a few in Europe and Africa. They are absent in Madagascar, Australia and Polynesia alone.
The extent of the genus Rhamnus is controversial. The buckthorn trees ( frangula ) are often seen as a separate genus. There are different classifications of the genus Rhamnus . Some authors share the genus Rhamnus s. l. in two subgenus Rhamnus and Frangula , which are further divided into sections. The following classification follows the system according to Suessenguth 1953, i.e. even before molecular genetic data were available:
- Subgenus Frangula (Miller) SFGray :
- The flowers are five-fold and hermaphroditic. The seeds are not furrowed and the cotyledons are thick. The buds do not have any bud scales. Leaves and branches are alternate. The main distribution area is the Pacific North America, beyond that Africa, East Asia, Central and South America.
- Subgenus Rhamnus (Syn .: Eurhamnus Dippel ):
- The flowers are always unisexual and the species are diocesan . The seeds are deeply furrowed. The germination takes place epigeal and the cotyledons are thin. The leaf position is alternate or opposite. Bud scales are present. The main focus is on East Asia.
Choice of types:
- Holly buckthorn or evergreen buckthorn ( Rhamnus alaternus L. )
- Alpine buckthorn ( Rhamnus alpina L. ): Without spines and with four-fold flowers from the southern European mountains.
- Purgier buckthorn or just buckthorn or buckthorn ( Rhamnus cathartica L. ): An upright shrub with large, sometimes downy, hairy leaves and fleshy fruits.
- Rhamnus crocea Nutt. : Occurrence in the southwest of the USA and northwest of Mexico.
- Rhamnus fallax Boiss. : Occurrence from Carinthia to Greece, without thorns.
- Buckthorn ( Rhamnus frangula L. , Syn .: Frangula alnus Mill. )
- Balearic buckthorn ( Rhamnus ludovici-salvatoris Chodat , Syn .: Rhamnus balearica (DC.) Optional ): Occurrence in Mallorca and in eastern Spain (near Valencia).
- Rhamnus lycioides L.
- Rhamnus myrtifolia Willk. : It only occurs in Spain.
- Dwarf buckthorn ( Rhamnus pumila Turra ): Small-leaved dwarf shrub of the southern and central European mountains.
- Purgier buckthorn ( Rhamnus purshiana DC. , Syn .: Frangula purshiana (DC.) A.Gray ): It occurs in British Columbia , Washington , Oregon , Idaho , Montana and in California.
- African buckthorn ( Rhamnus prinoides L'Hér. )
- Rhamnus rupestris Scop. (Syn .: Frangula rupestris (Scop.) Schur ): It occurs in Italy and on the Balkan Peninsula.
- Rock buckthorn ( Rhamnus saxatilis Jacq. ): Densely branched and thorny species with very small leaves, occurs mainly in the mountains of Central and Southern Europe.
use
The oil from the seeds is used to make lubricating oil, printing ink and soap. The roots and leaves of some species are used as remedies. The fruits of some species, Purgier buckthorn , holly buckthorn , rock buckthorn , dye thorn ( Rhamnus infectorius ), are used for dyeing.
proof
literature
- Thomas Gaskell Tutin : Rhamnus L. In: Th. G. Tutin and others: Flora Europaea. Volume 2, pp. 244-245. Cambridge University Press 1968.
- Schütt, Weisgerber, Schuck, Lang, Stimm, Roloff: Encyclopedia of Shrubs . Nikol, Hamburg 2006, ISBN 3-937872-40-X , p. 237-239 .
Individual evidence
- ↑ a b c d e f Schütt et al .: Encyclopedia of Shrubs. P. 238.
- ↑ a b c d e f g Yilin Chen, Carsten Schirarend: Rhamnaceae. Rhamnus. Pp. 139–148 - the same text online as the printed work , In: Wu Zheng-yi, Peter H. Raven, Deyuan Hong (ed.): Flora of China. Volume 12 - Hippocastanaceae through Theaceae , Science Press and Missouri Botanical Garden Press, Beijing and St. Louis, 2007, ISBN 978-1-930723-64-1 .
- ↑ Gordon Cheers (ed.): Botanica trees & bushes . Tandem Verlag, 2006, ISBN 978-3-8331-2003-9 , pp. 718 .
- ↑ D. Medan, C. Schirarend: Rhamnaceae. In: Klaus Kubitzki (Ed.): The Families and Genera of Vascular Plants - Volume VI - Flowering Plants - Dicotyledons - Celastrales, Oxalidales, Rosales, Cornales, Ericales. 2004, ISBN 3-540-06512-1 , p. 327.
- ↑ K. Suessenguth: Rhamnaceae . In: A. Engler, K. Prantl (Ed.): The natural plant families . 2nd Edition. tape 20 d. Duncker & Humblot, Berlin 1953 (quoted from Schütt et al .: Encyclopedia of Bushes. P. 239).
- ^ Erich Oberdorfer : Plant-sociological excursion flora for Germany and neighboring areas. 8th edition. Verlag Eugen Ulmer, Stuttgart 2001, ISBN 3-8001-3131-5 , p. 652.
- ^ Elbert L. Little: Minor Western Hardwoods (= Atlas of United States Trees . Volume 3 ). US Government Printing Office, 1976, Map 150-SW, Rhamnus crocea , hollyleaf buckthorn.
- ↑ a b Rhamnus in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved April 29, 2017.
- ↑ Juicy green from buckthorn berries on materialarchiv.ch , accessed on January 23, 2017.
