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Hazel (Corylus)

Family:

Birch family (Betulaceae)

Flowering period:

January to April

Distribution:

Distributed in the northern hemisphere in woods, hedges and gardens, medium sized shrub or tree, forest companions, occurs in the plains to upland areas, especially along forest edges

Appearance:

deciduous multi-stemmed shrubs or single-stemmed trees, deciduous leaves are simple, the leaf blade is broadly ovate, base often heart-shaped (cordate), double serrated leaf margin, lower leaf surface usually covered with fine hair, male inflorescences = catkins standing on the branches in grape-like groups, above the catkins are the bud-shaped female flowers with striking red style

Important species in Europe:

Corylus avellana (hazel): often present as the ornamental (Corylus avellana 'Contorta'), the well-known nut mainly originate from the “filbert” (Corylus maxima) that is widespread in south-eastern Europe and Asia Minor and more cold-sensitive than the common hazel.

Corylus colurna (Turkish hazel): native in southeastern Europe and Asia Minor, is also planted as ornamental in Europe.

Allergenicity:

moderate allergen potency and presence, frequent cross-reactions to hazelnut (food allergy) and the pollen of birch, alder and hornbeam; major allergen Cor a1

Link zum Pollenatlas: Corylus avellana

Wissenschaftlicher Beirat:
Ass. Prof. Dr. Siegfried Jäger (Medizinische Universität Wien)
Univ. Prof. Dr. Reinhart Jarisch (Floridsdorfer Allergie Zentrum)
Mag. Matthias Werchan (Charité Berlin)
Prof. Dr. med. Karl-Christian Bergmann (Charité Berlin)

Quellen:

Österreichischer Pollenwarndienst, Medizinische Universität Wien, Österreich
Charité, Allergie-Zentrum-Charité, Klinik für Dermatologie, Venerologie und Allergologie, Berlin, Deutschland
Wikipedia
www.alles-zur-allergologie.de
22 Jahre Blüh- und Fruktifikationsuntersuchungen der Waldbaumarten im Lehrforst Ofenbach/Rosalia. R. Litschauer. 2010. Bundesforschungs- und Ausbildungszentrum für Wald, Naturgefahren und Landschaft, BFW-Berichte 144, 36 pp.
Waldbau auf soziologisch-ökologischer Grundlage. H. Mayer 1977. Gustav Fischer Verlag, Stuttgart – New York, 482 pp.

pollinating male catkins (Image rights: Katharina Bastl)
pollinating male catkins (Image rights: Katharina Bastl)
female flowers with red carpel and catkin (Image rights: Katharina Bastl)
female flowers with red carpel and catkin (Image rights: Katharina Bastl)
leave of the hazel (Image rights: Katharina Bastl)
leave of the hazel (Image rights: Katharina Bastl)
seed - hazelnut (Image rights: Katharina Bastl)
seed - hazelnut (Image rights: Katharina Bastl)
hazel pollen as one of the first meadow for bees (Image rights: Katharina Bastl)
hazel pollen as one of the first meadow for bees (Image rights: Katharina Bastl)
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