''Petasites albus'', the white butterbur, is a

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

species in the family ''

Asteraceae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...

''. It is native to central Europe and the Caucasus.

Description

''Petasites albus'' is a perennial rhizomatous herb, with large suborbicular (almost round) leaves covered with lax cottony hairs. The flower heads are compact racemes of composite flowers or capitula with white

ligules A ligule (from "strap", variant of ''lingula'', from ''lingua'' "tongue") is a thin outgrowth at the junction of leaf and leafstalk of many grasses (Poaceae) and sedges. A ligule is also a strap-shaped extension of the corolla, such as that of a ...

. They are

dioecious Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproductio ...

, the male plants often more common than the females, as in the British range.

Distribution

The native range of ''Petasites albus'' is the mountains of central Europe and the Caucasus. It was first recorded in Sweden in Skåne in 1737 (Nordstedt 1920). In the British Isles it is a neophyte, introduced by the 17th century and naturalized in Yorkshire by 1843, but now predominantly distributed in North-east Scotland.

Habitat

It prefers damp soils in deciduous forests, mountain pastures, springs and streamsides, roadside verges and other areas of rough ground. White butterbur

References

albus Albus may refer to: * Albus (surname) * Albinus (cognomen), or Albus, a Latin surname * Albus (coin), ''groschen'' coin of the Holy Roman Empire * Albus, a Geomantic figure * 'Albus', a cultivar of Rosemary Entertainment * Albus Dumbledore ...

Flora of the Caucasus {{Senecioneae-stub