Double fluted hawthorn ( Crataegus laevigata )
The hawthorn ( Crataegus ) are a genus of shrubs or small trees of maloideae (Pyrinae) within the family of Rosaceae (Rosaceae). There are 200 to 300 species in the temperate climates of the northern hemisphere . The main area of distribution is in North America , especially in the eastern part. There are around 22 differentiated species in Europe and three in Germany , the differences between which are mostly only perceived by experts. Since the species can easily hybridize with one another within the individual regions , a reliable determination is difficult.
The German name Hawthorn has either, especially in the free state of lush bush and the existing sprout thorns or on the bright bark in contrast to the white flowers blackthorn called blackthorn out. The botanical name Crataegus goes back to the Greek κράταιγος ( krataigos ). The natural philosopher Theophrastus used this name to describe a type of shrub with edible fruits that grew on Mount Ida in Asia Minor. It is no longer possible to clarify from the text what today's species was meant by this name, but it was probably a hawthorn species with edible fruits, for example the azarol thorn ( Crataegus azarolus ), but possibly also the medlar . The ancient Greek krataiós means "strong" or "firm" and refers to the hard wood of this plant.
In addition to the designation hawthorn , which has become a scientific standard, there are a number of other German names such as Hagedorn (from Middle High German hagendorn ), Heckendorn , Weißheckdorn ; regional also Christian mandrel , Hagapfel , Hagäpfli , Heinzelmännerchen , flour tree , Mehlbeere (not to be confused with the actual flour berries ( Sorbus spp. )), flour mandrel , Mehlkübeli , Mehlfässel , Mehlfässl , haw , Mehlwieken , Wibelken , Wubbelken , Wyßdorn , fence mandrel . All of these names refer to the native species. Hag is etymologically derived from Hag (from an area surrounded by hedges).
As a genus , hawthorns are comparatively uniform and easy to identify. Hawthorns are found in the temperate climate zones of the northern hemisphere in forests and bushes, and are also cultivated in parks and gardens. They are deciduous shrubs or small, round-crowned trees that are densely branched and usually thorny . Their bark is smooth, green-brown to dark brown and scaly and cracked with age. The trunks of old trees are often spannrückig furrowed Längswülstig and deep. Their wood is hard and heavy. The alternate leaves are often conspicuously serrated, deeply incised or curved. The distinctive white, rarely pink or red flowers are in umbels panicles ; the individual flowers are 0.7 to 2.5 centimeters wide. The small apple fruits , mostly called berries, are 0.7 to 2.0 centimeters tall and usually red or orange, with some species blue, black or yellow. They contain one to five stone cores clumped together. Their flesh is usually dry and floury, only a few species are juicy.
The individual species are difficult to distinguish because, on the one hand, they split into many subspecies and varieties (clan formation), between which there are in turn transitional forms , and, on the other hand, all species - at least within the individual regions - easily and often hybridize with one another . Depending on the count, the number of species given in descriptions of the genus can increase to a multiple of the number range from 200 to 300 given above.
In the external systematic classification of the genus hawthorn, the assignment to the subfamily and the tribe is undisputed. According to morphological and molecular results, the medlar ( Mespilus germanica ) is very closely related . The monotypical genus Mespilus (a suspected second species, Crataemespilus x canescens (originally Mespilus canescens ) was found to be a hybrid of introduced European medlars and a North American hawthorn species) is now often included in the genus Crataegus ; but this is controversial. If one follows the view, the medlar would be another hawthorn species, then Crataegus germanica (L.) K. Koch, in the (monotypical) section Mespilus . According to molecular data, the morphologically very different genus Amelanchier ( rock pear ) (including two small, closely related genera) is closely related to the genus of hawthorns in the broader sense .
On the other hand, the internal systematic division of the genus has proven to be very difficult, which prompted WH Camp to create the term “Crataegus problem” in the 1940s .
The Crataegus Problem
The different types of plants have different tendencies to crossbreed . This tendency is pronounced in many genera of the rose-like and in these again especially in the hawthorn. Different hawthorn species that come into contact with each other easily cross each other even without human tutoring; this also applies to species from widely separated regions.
Hawthorn specimens resulting from a cross are often polyploid instead of diploid . In Central Europe, for example, diploid specimens of all six species described in the corresponding section can be found; Polyploid specimens have been found for Crataegus macrocarpa Hegetschw. , C. monogyna Jacq. , C. rhipidophylla Gand. and C. subsphaericea Gand. described. Polyploid hawthorns, on the other hand, often reproduce apomictically through agamospermia , so that all offspring are genetically identical clones of the mother plant.
This leads to a number of problems when naming species. Species that are considered to be independent can, for example, turn out to be single crossed specimens or as clone populations or as variants of another species that has foreign characteristics acquired through crossbreeding and subsequent selection. Verification is often difficult. Individual crossing specimens can be exposed through reproduction and the associated splitting of characteristics that is not to be expected for consolidated species ; serious botanists meanwhile do not describe any new species only on the basis of individual records. These methods are unsuitable for clone populations and for consolidated subspecies that have arisen from trait crossbreeding. Both variants reproduce with single characteristics and both often form larger populations. An indication can be the limited distribution of a population (so-called microspecies ), but this is not clear either as an exclusion or an inclusion criterion: On the one hand, an independent species can only be distributed to a limited extent; on the other hand, clone strains of the Crataegus are found in North America, for example crus-galli L. described with a large distribution area.
These circumstances lead to great uncertainties both in the division of the genus into sections and in the identification of species. Until around 1920, botanists tended to describe cases of doubt as separate species. With the emergence of evidence of hybridization and polyploidy, a rethink began that led to a review and severe reduction of the accepted species. The results are still highly controversial. Species numbers of around 200 are most common; however, the range of the specified number of species ranges from 100 to 1000. Improved results are now likely to be achieved mainly through genetic comparisons.
Phylogeny and Taxonomy
The type species of the genus Crataegus is Crataegus oxyacantha L. This is a problematic name that has been interpreted differently by different authors over time. Investigations based on the type material in the Linnaeus herbarium have shown that it is a plant that will later be known as Crataegus calycina subsp. curvisepala (today: Crataegus rhipidophylla ) has been described again (not, as previously long believed, Crataegus laevigata ). The name Crataegus oxyacantha was suppressed by the ICBN due to this lack of clarity (nomen utique rejiciendum, nom.rejic.), It no longer refers to a species. In traditional taxonomy, the genus hawthorn is divided into about 15 sections, and these in turn are divided into a large number of series . The delimitation of the sections and series has been controversial for a long time and has not yet been conclusively clarified. Older systems such as the one used by Phipps and colleagues in 1988 are now outdated and are only of historical interest; they differentiated 15 sections with 40 series. The modern structure is based on the system developed by Phipps and colleagues 2003. According to this, there are 4 sections with over 60 species in the Old World, while 11 sections with significantly more than 100 species live in the New World. This structure was largely confirmed in phylogenomic studies (based on the comparison of homologous DNA sequences). However, the classification of the species groups from eastern North America, which despite substantial morphological differences, are genetically closely related, turned out to be problematic. There are various possible reasons for this, but the most likely is a long, extensive hybridization of species from different sections with one another. For a few strongly deviating species with unclear assignment, an emergence from hybridization of American species with introduced European hawthorns that was only recently made can be made probable.
The subdivision into sections shown below, which is based on the sources mentioned, is not certain, there may still be changes in some places in the coming years. The structure in the Flora of North America (by James B. Phipps) is comparable. All European species belong to the Crataegus section :
- Mespilus Section . monotypical, only type the medlar . Caucasus, Asia Minor, Southeast Europe. alternatively, as a separate genus Mespilus construed
- Brevispinae section . monotypical, only species Crataegus brachyacantha . eastern North America (Louisiana). (Affiliation of some other species is disputed).
- Hupehenses section . monotypical, only species Crataegus hupehensis . East Asia (China). according to the genetic data, possibly belonging to the Crataegus section .
- Section Cuneatae . monotypical, only species Crataegus cuneata . East Asia (Japan, Chima). not yet genetically tested.
- Section of Crataegus . Eurasia and North America (Series Apiifoliae )
- Section Sanguineae . East asia
- Section Douglasianae (syn. Douglasiae ). western north america. Species with black colored fruits.
- Macacanthae section . eastern north america. The Anomalae series includes (presumably) species that emerged as hybrids with species from other sections.
- Section Coccineae . eastern north america. The most species-rich clade.
The grouping of all North American species in a common section or subgenus Americanae is no longer represented in this form today. However, some taxonomists continue to use this name to unite the probably more closely related sections of eastern North America, the previously controversial sections Coccineae and Macanthae .
The hawthorn in Central Europe
Central European species
In Central Europe are, according to the count of three or six hawthorn species native. Three species were originally native here, from which three other species emerged through wild crossing (see also nature hybrids ).
Of the three original species, two are generally known: the single-fluted hawthorn ( Crataegus monogyna Jacq. ) And the double-fluted hawthorn ( Crataegus laevigata (Poir.) DC. ) (Syn .: C. oxyacantha auct. ). The large-calyzed hawthorn ( Crataegus rhipidophylla Gand. ) (Syn .: Crataegus rosiformis Janka , C. curvisepala Lindm. ) Is mentioned almost exclusively in the specialist literature . Popular scientific identification books and lexicons describe only the first two types or even claim that there are only two types in Central Europe.
The three types of crossbreeding are mentioned exclusively in the specialist literature: the large-fruited hawthorn ( Crataegus x macrocarpa Hegetschw. ) - developed from the large-calyx and double-fluted hawthorn -, the middle hawthorn or bastard hawthorn ( Crataegus x media Bechst. ) - emerged from the single-fluted hawthorn and the double-fluted hawthorn - as well as the different- toothed hawthorn ( Crataegus x subsphaericea Gand. ) (Syn .: C. kyrtostyla Fingerh. ) - emerged from the single-fluted and large-calyzed hawthorn. In some areas they can represent a large part of the hawthorn flora and - like the first three species mentioned - form comparatively pure stands. These are stabilized hybrid families (hybrid species or Nothospecies ). Since they continue to hybridize with each other and with the original species, there is an almost inconceivable abundance of transitional forms, many of which have been given their own names. Their taxonomy is, however, uncertain and highly controversial between different botanists. Many botanists therefore no longer differentiate between these “small species”, but group them together to form diverse aggregated species . The species Crataegus monogyna becomes Jacq. and its subspecies the aggregated species Crataegus monogyna Jacq. sl
While the hawthorn species are endangered or threatened with extinction only in a few German federal states , the diversity of the hawthorn is endangered. In the course of the 1950s and 1960s in particular, a large part of the hedges that border the fields and pastures were removed in rural regions , and with them an important habitat for the hawthorn and the fauna that inhabit it. In the course of the ecological movement , this trend was halted and a number of hedges were planted. For these new plantings, however, Germany-wide uniform tree nursery products were used, ecotypes adapted to the area were not taken into account. At Hawthorn which concerned the bargain only the species monogyna and Crataegus laevigata that other species were not planted. Since the 2000s, however, there has also been a rethink here; Attention should now be paid to the planting of all species and generally only planting material should be used that was obtained from stands typical of the area in the same natural area .
In addition to the native species, wild specimens of foreign species can also be found in Central Europe. For example, the “List of Wild Vascular Plants of the State of Berlin” lists the North American cockspur hawthorn ( Crataegus crus-galli L. ) as “occurring spontaneously in the past 10 years, but neither currently nor at a previous point in time has it been established as established”. It remains to be seen whether such species can settle in the long term.
The Central European species
The Central European hawthorn species are very similar: Carl von Linné himself assumed the existence of only one species, which he called Crataegus oxyacantha - a species name that was later rejected by the International Botanical Congress due to the unclear assignment to a particular plant . They love sunlight, but also thrive in partial shade and are found in hedges, bushes, light deciduous and pine forests, as well as gardens and parks. They grow as shrubs or small trees, can be several meters high and up to 500 years old and are always reinforced with thorns up to 2.5 cm long . Their leaves are egg-shaped to diamond-shaped, wedge-shaped at the base, slightly to deeply indented with three to five, less often up to seven lobes and usually also somewhat serrated. They bloom mostly white in May and June, rarely red; the flowers are 0.7–1.5 cm wide and have a noticeable smell of mouse urine (definition of the German Pharmacopoeia). The apple fruits ripen in August and September and often stay on the tree until spring . They are red, almost spherical, 0.7–1.2 cm long, contain 1 to 3 seeds, and taste sour and sweet; the pulp is yellow and floury. (For the differences between the species - see the respective "Art Articles", if available.)
Hawthorns are home to 54 species of caterpillars .
Use of fruits, flowers, leaves and wood
The fruits of the hawthorn can be eaten raw and have a sour and sweet taste, but are very floury. They can be made into compote or jelly and are suitable for mixing with other fruits because they gel well. Mixed with other fruits, they can also be processed into vitamin-rich juice or syrup . In times of need the fruits were as Mus eaten and the dried fruit pulp as a flour additive used in bread making. The kernels served as a coffee substitute . The dried flowers, leaves and fruits are used as a tea or alcoholic extract for cardiovascular disorders (see section: Use in medicine (phytotherapy)) . In China, the fruits are often made into sweets.
Use as a wood
In gardens and parks, the hawthorn is a popular ornamental plant because of its beautiful shape and leaves and its abundant floral and fruit decorations, which is grown in many cultivars . Thus, besides simple white flowering inputs and two handles leagues hawthorns and red flowering varieties ( hawthorn ), varieties with double flowers, also in white ( Crataegus laevigata 'and red (, Plena) Crataegus monogyna , Karmesina Plena', Crataegus laevigata Paul's Scarlet ') , Varieties with a narrow, upright shape ( Crataegus monogyna 'Stricta') and many others. The hawthorn is used both as a specimen plant and as a hedge plant. It is an excellent hedge that can withstand strict pruning very well; then it does not bloom as profusely. The ecological value of the hawthorn is very high; it is an important food donor and habitat for numerous small animals. In Central Europe it provides a livelihood for around 150 insect species, a good 30 songbird species and many small mammals (for comparison: oak ( Quercus spec. ) Approx. 300, hornbeam ( Carpinus betulus ) approx. 30 insect species).
Asian and North American species are also popular as ornamental plants . They often have larger fruits and better autumn colors. The cockspur hawthorn ( Crataegus crus-galli L. ) with the longest thorns (up to 8 cm) of all hawthorns and the scarlet hawthorn ( Crataegus pedicellata coffin ) from North America are popular. However, their ecological value is comparatively low. 32 bird species alone eat the fruits of the native single-fluted hawthorn; the fruits of the leather-leaved hawthorn , also known as "Lavalles hawthorn" ( Crataegus × lavallei Herincq ex Lavallée ), which is often used in horticulture , are only eaten by three species of birds.
In rural areas , the hawthorn was an important plant of the border hedges, which separated fields , meadows, paths and properties from each other due to its longevity, very good cut tolerance and of course its thorns . Not much of that remains (see above - “The hawthorn in Central Europe - Central European species”).
Use in medicine (phytotherapy)
The hawthorn was first mentioned as a remedy in the European cultural area in the 1st century AD by Pedanios Dioscurides . The use of medicinal herbs such as hawthorn is also part of other medical systems such as traditional Chinese medicine ; Indian tribes in America are also known to use hawthorn.
In herbal medicine (phytotherapy) the following are used:
- Branches bearing the whole or cut flowers ( crataegi folium cum flore )
- The false fruits ( crataegi fructus )
Ingredients are oligomeric procyanidins (OPC), glycosidic flavones such as vitexin and vitexin rhamnoside and glycosidic flavonols such as rutin and hyperoside ; there are also tannins with a content of 0.5 to 1%.
The main indication is chronic myocardial insufficiency with the resulting low blood pressure in stages I and II as defined by the New York Heart Association (NYHA). Popularly, hawthorn leaves with blossoms are also widely used - for example for nervousness .
Hawthorn on the one hand increases the contraction force of the heart , one speaks of a positive inotropic effect, on the other hand it expands the blood vessels , especially the coronary arteries, and thus improves the oxygen supply to the heart muscle. Many heart diseases are due to a lack of oxygen in the heart muscle. Angina pectoris and myocardial infarction in particular are considered to be circulatory disorders of the heart muscle. The effect is partly comparable with digitalis (positive inotropic), on the other hand with an ACE inhibitor (vasodilator and therefore stimulates blood circulation), but via completely different mechanisms of action and with apparently much better tolerability, since the undesirable effects (including accumulation) of cardiac glycosides are eliminated .
The effect is mainly based on oligomeric proanthocyanidins (OPC) and is delayed compared to other substances that affect the heart . To make it, the ends of the branches with the flowers and leaves are cut off and dried to make ready-made preparations or tea . The hawthorn was named Medicinal Plant of the Year in 1990 .
Many mythical and ritual meanings of the hawthorn have passed down from different epochs. The different names result from its use as a hedge plant to demarcate properties and from its power to ward off evil spirits or to protect them from being hexed. In Roman antiquity he was sacred to Ianus . A branch of hawthorn placed in the window protected children from the nocturnal streaks . It is also considered the elves ' apartment , which is why in earlier times in Germany scraps of cloth and hair were woven into the branches of the hawthorn, as this should induce the elves to do good deeds on the donor. Hawthorn cradles are designed to prevent children from being exchanged by evil fairies.
- “We only saddle at midnight.
- I rode far from Bohemia:
- I got up late
- and want to take you with me! "-
- “Oh, Wilhelm, get in quickly!
- The wind blows through the hawthorn,
- in, in my arms,
- Dearest, to warm up! "
- "Let go through the hawthorn,
- let go, child, let go!
- The black paws, the spur rattles;
- I am not allowed to live here.
- Come on, apron, jump and swing
- on my pony behind me!
- Got a hundred miles to-day
- rush to the bridal bed with you. "
- "Great luck and happiness now laughs at the Rhine,
- because Hagen, the Grimme, may be so funny!
- The hawthorn no longer stings;
- he was appointed as the wedding caller. "
- “Now hear the voice that calls for pity
- Macheath is not here under the hawthorn
- not under beeches, no, in a crypt
- this is where the wrath of fate brought him "
There is a ballad by Wilhelm Raabe , Der Hagedorn .
The hawthorn and its blossom also play an important role in Marcel Proust's In Search of Lost Time . But no matter how long I lingered in front of the hawthorn, smelled it, imagined its invisible, unchangeable scent in my thoughts that didn't know what to do with it ... Its abundance of flowers is a leitmotif for the narrator's childhood memories.
The following list of species of the genus of hawthorn leads consciously beside the botanical name of the author names with on. This is important because with the variety of shapes and the many crossings in this genus, this additional information is essential. Many names have been given multiple times - for example Crataegus oxyacantha [ L. / auct. (non L.) / (Poir.) DC / Jacq. / Gand. ] and Crataegus sanguinea [ JG Cooper / Pall. / Schrad. / Torr. & A. Gray ]; only one is still valid. In the case of mentions without an author's name, however, it cannot be assumed that the validly named species is meant. For example, in popular scientific literature, the botanical name Crataegus oxyacantha usually incorrectly stands for the double-fluted hawthorn, but in fact the basionym of the large-fruited hawthorn is hidden behind this name .
The following list of species is necessarily incomplete; the range of the individual species is roughly shown as follows:
Systematics of hawthorns
- Information about Crataegus at FloraWeb.de
- Identification aids for identification-critical taxa for the flora of Germany
Sources and further reading
- Gregor Aas , Andreas Riedmüller: GU-Naturführer Trees: Recognize and identify deciduous and coniferous trees in Europe . Gräfe and Unzer (GU), Munich 1995, ISBN 978-3-7742-1016-5 (GU nature guide).
- C. Frank Brockman (Author), Rebecca Marrilees (Illustrator): Trees of North America . St. Martin's Press, New York 2001, ISBN 978-1-58238-092-6 .
- Eve Marie Helm: Field, Forest and Meadow Cookbook . 5th edition. Heyne, Munich 1983, ISBN 978-3-453-66005-2 .
- Hugh Johnson: The Big Book of Trees . Hallwag, Bern 1974, ISBN 978-3-444-10153-3 .
- Bruno P. Kremer , Gunter Steinbach : Shrub trees . Eugen Ulmer; Mosaik, Niedernhausen 2002, ISBN 978-3-8001-4275-0 (Steinbach's natural guide).
- Christoph Needon: Wild Fruit Booklet . 2nd Edition. Verlag für die Frau, Leipzig 1996, ISBN 978-3-7304-0347-1 .
- Ursula Nikla-Pahlow: Wild Fruit Compass . Gräfe and Unzer, Munich 1982, ISBN 978-3-7742-3811-4 .
- Birgit Groth, Birgit Seitz, Michael Ristow (2003): Tree and shrub species suitable for nature conservation for use in compensation measures in the open landscape in Brandenburg. Nature conservation and landscape management in Brandenburg 12 (1): 28–30. PDF
- Photos, distribution maps of the hawthorn species (North America), taxonomy, habitats (values) and related links , PLANTS database (English)
- Description of the genus as well as the species and further links , Flora of China . ( PDF file , 160 kB) (English)
- 2006 Botany Conference: Crataegus classification , at Botanyconference.org (English)
- Hermann Paul: German Dictionary, Halle ad Saale 1921, p. 111
- Heinrich Marzell : Dictionary of German plant names . tape 1 (5) . S. Hirzel, Leipzig 1943.
- James B. Phipps (2016): Studies in Mespilus, Crataegus, and × Crataemespilus (Rosaceae), II. The academic and folk taxonomy of the medlar, Mespilus germanica, and hawthorns, Crataegus (Rosaceae). Phytotaxa 260 (1): 25-35. doi: 10.11646 / phytotaxa.260.1.3
- Jürgen Martin: The 'Ulmer Wundarznei'. Introduction - Text - Glossary on a monument to German specialist prose from the 15th century. Königshausen & Neumann, Würzburg 1991 (= Würzburg medical-historical research. Volume 52), ISBN 3-88479-801-4 (also medical dissertation Würzburg 1990), p. 135.
- James Phipps (2016): Studies in Mespilus, Crataegus, and × Crataemespilus (Rosaceae), I. differentiation of Mespilus and Crataegus, expansion of × Crataemespilus, with supplementary observations on differences between the Crataegus and Amelanchier clades. Phytotaxa 257 (3): 201-229. doi: 10.11646 / phytotaxa.257.3.1
- Eugenia YY Lo, Saša Stefanovič, Timothy A. Dickinson (2007): Molecular Reappraisal of Relationships Between Crataegus and Mespilus (Rosaceae, Pyreae) —Two Genera or One? Systematic Botany 32 (3): 596-616. doi: 10.1600 / 036364407782250562
- Jean I. Byatt (1974): Application of the names Crataegus calycina Peterm. and C. oxyacantha L. Botanical Journal of the Linnean Society 69 (1): 15-21. doi: 10.1111 / j.1095-8339.1974.tb01610.x
- James B. Phipps, Kenneth R. Robertson, Paul G. Smith, Joseph R. Rohrer (1988): A checklist of the subfamily Maloideae (Rosaceae). Canadian Journal of Botany 68: 2209-2269.
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- Eugenia YY Lo, Saša Stefanovič, Knud Ib Christensen, Timothy A. Dickinson (2009): Evidence for genetic association between East Asian and western North American Crataegus L. (Rosaceae) and rapid divergence of the eastern North American lineages based on multiple DNA sequences. Molecular Phylogenetics and Evolution 51: 157-168. doi: 10.1016 / j.ympev.2009.01.018
- James B. Phipps: Rosaceae, 64. Crataegus Linnaeus. Flora of North America, vol. 9 online on June 30, 2015.
- Knud Ib Christensen (1992): Revision of Crataegus Sect. Crataegus and Nothosect. Crataeguineae (Rosaceae-Maloideae) in the Old World. Systematic Botany Monographs 35, 199 pp.
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- Richard Kenneth Brummitt (1986): Report of the Committee for Spermatophyta 30. Taxon, IAPT 35 (3), pp. 556-563.
- Helmut Hintermeier: The privet and his guests , in Allgemeine Deutsche Beekeeper newspaper , November 2008, p. 30 f.
- "The show garden in Wachtberg" , Deutsche Umwelthilfe , September 22, 2008
- Margret Wenigmann: Medicinal Plants . Urban & Fischer, Munich 1999, ISBN 3-437-55570-7 , pp. 215-216 .
- Margret Wenigmann: Medicinal Plants . Urban & Fischer, Munich 1999, ISBN 3-437-55570-7 , pp. 217 .
- M. H. Pittler, R. Guo, E. Ernst: Hawthorn extract for treating chronical heart failure. In: Cochrane database of systematic reviews (Online) , number 1, 2008, p. CD005312, doi: 10.1002 / 14651858.CD005312.pub2 . PMID 18254076 (Review) .
- Margret Wenigmann: Medicinal Plants . Urban & Fischer, Munich 1999, ISBN 3-437-55570-7 , pp. 216 .
- Margret Wenigmann: Medicinal Plants . Urban & Fischer, Munich 1999, ISBN 3-437-55570-7 , pp. 216-217 .
- Margret Wenigmann: Medicinal Plants . Urban & Fischer, Munich 1999, ISBN 3-437-55570-7 , pp. 215 .
- William Boericke: Handbook of the homeopathic materia medica . Basics and Practice, Heidelberg 1992, ISBN 978-3-8304-7205-6 , p. 275-276 . ; SR Phatak: Homeopathic Medicine . 2nd Edition. Urban & Fischer; Elsevier Science, Munich 2004, ISBN 978-3-89762-001-8 , pp. 234 .
- Ovid Fasti 6.165 ff.