Willow

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Willows
Weeping Willow
Weeping Willow
Plant Info
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta
Class: Magnoliopsida
Order: Malpighiales
Family: Salicaceae
Genus: Salix L.

Species
About 350, including:

Salix acutifolia - Violet Willow
Salix alaxensis - Alaska Willow
Salix alba - White Willow
Salix alpina - Alpine Willow
Salix amygdaloides - Peachleaf Willow
Salix arbuscula - Mountain Willow
Salix arbusculoides - Littletree Willow
Salix arctica - Arctic Willow
Salix atrocinerea
Salix aurita - Eared Willow
Salix babylonica - Peking Willow
Salix bakko
Salix barrattiana - Barratt's Willow
Salix bebbiana - Beaked Willow
Salix boothii - Booth Willow
Salix bouffordii
Salix brachycarpa - Barren-ground Willow
Salix cacuminis
Salix canariensis
Salix candida - Sage Willow
Salix caprea - Goat Willow
Salix caroliniana - Coastal Plain Willow
Salix chaenomeloides
Salix chilensis
Salix cinerea - Grey Sallow
Salix cordata
Salix daphnoides
Salix discolor - Pussy Willow
Salix eastwoodiae - Eastwood's Willow
Salix eleagnos
Salix eriocarpa
Salix eriocephala - Heartleaf Willow
Salix exigua - Sandbar Willow
Salix foetida
Salix fragilis - Crack Willow
Salix futura
Salix geyeriana
Salix gilgiana
Salix glauca
Salix gooddingii - Goodding Willow
Salix gracilistyla
Salix hainanica - Hainan Willow
Salix helvetica - Swiss Willow
Salix herbacea - Dwarf Willow
Salix hirsuta
Salix hookeriana - Hooker's Willow
Salix hultenii
Salix humboldtiana - Chile Willow
Salix humilis - Upland Willow
Salix integra
Salix interior
Salix japonica
Salix jessoensis
Salix koriyanagi
Salix kusanoi
Salix lanata - Woolly Willow
Salix lapponum - Downy Willow
Salix lasiandra - Pacific Willow
Salix lasiolepsis - Arroyo Willow
Salix lucida - Shining Willow
Salix magnifica
Salix matsudana - Chinese Willow
Salix miyabeana
Salix mucronata
Salix myrtilloides - Swamp Willow
Salix myrsinifolia - Dark-leaved Willow
Salix myrsinites - Whortle-leaved Willow
Salix nakamurana
Salix nigra - Black Willow
Salix pedicellaris - Bog Willow
Salix pentandra - Bay Willow
Salix petiolaris - Slender Willow
Salix phylicifolia - Tea-leaved Willow
Salix planifolia- Planeleaf Willow
Salix polaris - Polar Willow
Salix pseudo-argentea
Salix purpurea - Purple Willow
Salix pyrifolia - Balsam Willow
Salix reinii
Salix repens - Creeping Willow
Salix reticulata - Net-leaved Willow
Salix retusa
Salix rorida
Salix rosmarinifolia - Rosemary-leaved Willow
Salix rupifraga
Salix salicicola
Salix schwerinii
Salix scouleriana - Scouler's Willow
Salix sericea - Silky Willow
Salix serissaefolia
Salix serissima - Autumn Willow
Salix shiraii
Salix sieboldiana
Salix sitchensis
Salix subfragilis
Salix subopposita
Salix taraikensis
Salix tetrasperma
Salix thorelii
Salix triandra - Almond Willow
Salix udensis
Salix viminalis - Common Osier
Salix vulpina
Salix waldsteiniana
Salix wallichiana
Salix wilmsii
Salix woodii
Salix yezoalpina
Salix yoshinoi

The willows are deciduous trees and shrubs in the genus Salix, part of the willow family Salicaceae.

There are about 350 species in this genus worldwide, found primarily on moist soils in cooler zones in the Northern Hemisphere. The leaves are deciduous, often elongate but round to oval in a few species, and with a serrated margin. Willows are dioecious with male and female flowers appearing as catkins on different plants; the catkins are produced early in the spring, often before the leaves or as the new leaves open. The fruit is a small capsule containing numerous tiny (0.1 mm) seeds embedded in white down, which assists wind dispersal of the seeds. Willows are very cross-fertile and numerous hybrids are known, both naturally occurring and in cultivation.

Some smaller species may also be known by the common names osier and sallow; the latter name is derived from the same root as the Latin salix.

Some willows, particularly arctic and alpine species, are very small; the Dwarf Willow (Salix herbacea) rarely exceeds 6 cm in height, though spreading widely across the ground.

The Weeping Willow, very widely planted as an ornamental tree, is a cultivar, Salix × sepulcralis 'Chrysocoma', derived from a hybrid between the Chinese Peking Willow and the European White Willow.

Almost all willows take root very readily from cuttings or where broken branches lie on the ground. There are a few exceptions, including the Goat Willow and Peachleaf Willow. One famous example of such growth from cuttings involves the poet Alexander Pope, who begged a twig from a parcel tied with twigs sent from Spain to Lady Suffolk. This twig was planted and thrived, and legend has it that all of England's Weeping Willows are descended from this first one [1]. Willows are used as food plants by the larvae of some Lepidoptera species - see list of Lepidoptera which feed on Willows.

A number of willow species were widely planted in Australia in the past, notably as erosion control measures along watercourses. They are now regarded as an invasive weed and many catchment management authorities are removing them to be replaced with native trees [2].. [3].

Uses

Medicinal uses

The bark of the willow tree has been mentioned in ancient texts from Assyria, Sumer and Egypt as a remedy for aches and fever, and the Greek physician Hippocrates wrote about its medicinal properties in the 5th century BC. Native Americans across the American continent relied on it as a staple of their medical treatments.

The active extract of the bark, called salicin, was isolated to its crystalline form in 1828 by Henri Leroux, a French pharmacist, and Raffaele Piria, an Italian chemist, who then succeeded in separating out the acid in its pure state. Salicin is acidic when in a saturated solution in water (pH = 2.4), and is called salicylic acid for that reason.

In 1897 Felix Hoffmann created a synthetically altered version of salicin (in his case derived from the Spiraea plant), which caused less digestive upset than pure salicylic acid. The new drug, formally Acetylsalicylic acid, was named aspirin by Hoffmann's employer Bayer AG. This gave rise to the hugely important class of drugs known as non-steroidal anti-inflammatory drugs (NSAIDs).