Fallopia japonica (Houtt.) (= Reynoutria japonica Houtt.)

Japanese knotweed
Fallopia_japonica_01 Fallpia_japonica_02

Description 1

Perennial, herbaceous rhizomatous plant with hollow stalks of up to 3 m in height. Oval alternate petiolated leaves, truncated at the base, of 5-14 x 3-13 cm. Inflorescences in loose panicles. Flowers with whitish perianth, with 5 persistent tepals in fruiting, the 3 external alates. Androecium with 8 stamens and gynoecium with 3 long styles. Black coloured fruit, 4x2 mm approximately.

Biology 1

Flowers from August to September, with no visible seeds in Spain. Pollinated by insects. Dispersion, produced mainly by movement of earth contaminated with rhizomes. It can form hybrids with other species (Fallopia baldschuanica, Fallopia sachalensis), increasing genetic variability. Competitive adaptations: presence of reserve organs, rapid growth of vegetative organs, dense foliage that produces intense shading, gigantism and high photosynthetic performance, alleopathic substances and rapid regeneration of damage to leaves and stalks.

Habitat 1

Humid climates or, in Mediterranean environments, soil with edaphic humidity. Withstands intense winter cold, though unable to flower in Autumn cold with early frosts. Prefers fertile soil, rich in nitrogen. Requires moderate light, invades glades and shores of forest environments. In ripary areas, it is favoured by the euthrophication of the waters, the suppression of avenues by hydraulic works and the regulation of river and destruction of natural vegetation.

Sources 1

Spanish Catalogue of Exotic Invasive Species, Atlas of Exotic Invasive Plants in Spain.

Spanish Catalogue of Exotic Invasive Species - Flora 1

http://www.magrama.gob.es/es/biodiversidad/temas/conservacion-de-especies/especies-exoticas-invasoras/ce_eei_flora.aspx

Fuentes y Créditos

  1. Adaptado por INVASORES - administrador de un trabajo de (c) cartotragsatec, algunos derechos reservados (CC BY), http://natusfera.gbif.es/guide_taxa/485

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