Willow

"Salix" redirects here. For other uses, see Salix (disambiguation).

"Osier" redirects here. For the ghost town, see Osier, Colorado.

For other uses, see Willow (disambiguation).

Willow
Salix alba 'Vitellina-Tristis' Morton Arboretum acc. 58-95*1
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Rosids
Order:	Malpighiales
Family:	Salicaceae
Tribe:	Saliceae[1]
Genus:	Salix L.
Species
About 400.[2] See List of Salix species

Willows, sallows, and osiers form the genus Salix, around 400 species^[2] of deciduous trees and shrubs, found primarily on moist soils in cold and temperate regions of the Northern Hemisphere. Most species are known as willow, but some narrow-leaved shrub species are called osier, and some broader-leaved species are referred to as sallow (from Old English sealh, related to the Latin word salix, willow). Some willows (particularly arctic and alpine species) are low-growing or creeping shrubs; for example the Dwarf Willow (Salix herbacea) rarely exceeds 6 cm (2 in) in height, though spreading widely across the ground.

Willows are very cross-fertile, and numerous hybrids occur, both naturally and in cultivation. A well-known ornamental example is the Weeping Willow (Salix × sepulcralis), which is a hybrid of Peking Willow (Salix babylonica) from China and White Willow (Salix alba) from Europe.

Description

Willows all have abundant watery bark, sap which is heavily charged with salicylic acid, soft, usually pliant, tough wood, slender branches, and large, fibrous, often stoloniferous roots. The roots are remarkable for their toughness, size, and tenacity to life, and roots readily grow from aerial parts of the plant.

The leaves are typically elongated but may also be round to oval, frequently with a serrated margin. Most species are deciduous; semi-evergreen willows with coriaceous leaves are rare, e.g. Salix micans and S. australior in the eastern Mediterranean. All the buds are lateral; no absolutely terminal bud is ever formed. The buds are covered by a single scale, enclosing at its base two minute opposite buds, alternately arranged, with two small, opposite, scale-like leaves. This first pair soon fall, and the later leaves are alternately arranged. The leaves are simple, feather-veined, and typically linear-lanceolate. Usually they are serrate, rounded at base, acute or acuminate. The leaf petioles are short, the stipules often very conspicuous, looking like tiny round leaves and sometimes remaining for half the summer. On some species, however, they are small, inconspicuous, and fugacious (soon falling). In color the leaves show a great variety of greens, ranging from yellowish to bluish.

Flowers

Young male catkin

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 staminate (male) flowers are without either calyx or corolla; they consist simply of stamens, varying in number from two to ten, accompanied by a nectariferous gland and inserted on the base of a scale which is itself borne on the rachis of a drooping raceme called a catkin, or ament. This scale is oval and entire and very hairy. The anthers are rose colored in the bud but orange or purple after the flower opens, they are two-celled and the cells open longitudinally. The filaments are threadlike, usually pale yellow, and often hairy.

The pistillate (female) flowers are also without calyx or corolla; and consist of a single ovary accompanied by a small flat nectar gland and inserted on the base of a scale which is likewise borne on the rachis of a catkin. The ovary is one-celled, the style two-lobed, and the ovules numerous.

Cultivation

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 (Salix caprea) and Peachleaf Willow (Salix amygdaloides). 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.^[3]

Willows are often planted on the borders of streams so that their interlacing roots may protect the bank against the action of the water. Frequently the roots are much larger than the stem which grows from them.

Ecological issues

Willows are used as food plants by the larvae of some Lepidoptera species–see list of Lepidoptera that feed on willows.

A small number of willow species were widely planted in Australia, 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.^[4][5]

Willow roots grow widespread and are very aggressive in seeking out moisture; for this reason, they can become problematic when planted in residential areas, where the roots are notorious for clogging French drains, drainage systems, weeping tiles, septic systems, storm drains, and sewer systems, particularly older, tile, concrete, or ceramic pipes. Newer, PVC sewer pipes are much less leaky at the joints, and are therefore less susceptible to problems from willow roots; the same is true of water supply piping.^[6][7]

Uses

• Medicine. The leaves and bark of the willow tree have been mentioned in ancient texts from Assyria, Sumer and Egypt^[8] as a remedy for aches and fever,^[9] and the Ancient 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. This is because willows contain salicin, a substance that chemically resembles aspirin. It temporarily relieves headache, stomachache, and other body pain. Salicin is metabolized in to salicylic acid in the human body, which is a precursor of aspirin.^[10] In 1763 its medicinal properties were observed by the Reverend Edward Stone in England. He notified the Royal Society who published his findings. 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 compound in its pure state. 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).

• Manufacturing. Some of man's earliest manufactured items may have been made from willow. Basic crafts such as baskets, fish traps, wattle fences and wattle and daub house walls were often woven from osiers (rod-like willow shoots). One of the forms of welsh coracle traditionally uses willow in the 'lats'. Thin or split willow rods can be woven into wicker, which also has a long history. The relatively pliable willow is less likely to split while being woven than many other woods, and can be bent around sharp corners in basketry. Willow wood is also used in the manufacture of boxes, brooms, cricket bats (grown from certain strains of white willow), cradle boards, chairs and other furniture, dolls, flutes, poles, sweat lodges, toys, turnery, tool handles, veneer, wands and whistles. In addition tannin, fibre, paper, rope and string, can be produced from the wood.

• Food. Poor people at one time often ate willow catkins that had been cooked to form a mash.^[11]

Male catkin of Salix cinerea with bee

Woodbine caused by Honeysuckle on a Willow.

• Agriculture. Willow bark contains auxins (plant growth hormones), especially those used for rooting new cuttings. The bark can even be used to make a simple extract that will promote cutting growth. Willows produce a modest amount of nectar that bees can make honey from, and are especially valued as a source of early pollen for bees.
• Energy. Willow is grown for biomass or biofuel, in energy forestry systems, as a consequence of its high energy in-energy out ratio, large carbon mitigation potential and fast growth.^[12] Large scale projects to support willow as an energy crop are already at commercial scale in Sweden,^[13] and in other countries there are others being developed through initiatives such as the Willow Biomass Project in the US and the Energy Coppice Project in the UK.^[14] Willow may also be grown to produce Charcoal.
• Environment. As a plant, willow is used for biofiltration, constructed wetlands, ecological wastewater treatment systems, hedges, land reclamation, landscaping, phytoremediation, streambank stabilisation (bioengineering), slope stabilisation, soil erosion control, shelterbelt & windbreak, soil building, soil reclamation, tree bog compost toilet, wildlife habitat.
• Art. Willow is used as charcoal (for drawing) and in living sculptures. Living sculptures are created from live willow rods planted in the ground and woven into shapes such as domes and tunnels. Willow stems are used to weave baskets and 3 dimensional sculptures such as animals and figures. Willow stems are also used to create garden features such as decorative panel and obelisks.
• Religion. Willow is one of the "Four Species" used ritually during the Jewish holiday of Sukkot. In Buddhism, a willow branch is one of the chief attributes of Kwan Yin, the bodhisattva of compassion. Willow is also one of the "nine sacred trees" mentioned in Wicca and witchcraft, with several magical uses. In the Wiccan Rede, it is described as growing by water, guiding the dead to "The Summerland", a commonly used term in Wicca to refer to the afterlife. Christian churches in northwestern Europe often used willow branches in place of palms in the ceremonies on Palm Sunday.^[15]

_{Willow tree as seen as the main part of an heraldic escrutcheon over the main portal of a patrician house belonging to the Salis family in Chur, circa 1750.}

• Culture. In China, some people carry willow branches with them on the day of their Tomb Sweeping or Qingming Festival. Willow branches are also put up on gates and/or front doors, which they believe help ward off the evil spirits that wanders on Qingming. Legend states that on Qingming Festival, the ruler of Hades allows the spirits of the dead to return to earth. Since their presence may not always be welcome, willow branches keep them away.^[16] In traditional pictures of the Goddess of Mercy Guanyin she is often shown seated on a rock with a willow-branch in a vase of water at her side. The Goddess employs this mysterious water and the branch for putting demons to flight. Taoist witches also use a small carving made from willow wood for communicating with the spirits of the dead. The image is sent to the nether world, where the disembodied spirit is deemed to enter it, and give the desired information to surviving relatives on its return.^[17] The willow is a famous subject in many East Asian nations' cultures, particularly in pen and ink paintings from China and Japan.

A Gisaeng (Korean Geisha) named Hongrang, who lived in the middle of the Joseon Dynasty, wrote the poem "By the willow in the rain in the evening", which she gave to her parting lover (Choi Gyeong-chang).^[18] Hongrang wrote:

"...I will be the willow on your bedside."

In Japanese tradition the willow is associated with ghosts. It is popularly supposed that a ghost will appear where a willow grows. Willow trees are also quite prevalent in folklore and myths.^[19][20] In English folklore, a willow tree is believed to be quite sinister, capable of uprooting itself and stalking travellers. The Viminal hill, one of the Seven Hills Of Rome, derives it name from the Latin word for osier, viminia (pl.).

• Literature.

• In The Book of Psalms, Psalm 137 — "Upon the rivers of Babylon, there we sat and also cried in our remembering Zion. Upon the willows in the river's midst we hung our lyres." This Psalm is an ancient expression of Jews' yearning to return from the exile (Babylonian) to the Land of Zion.
• Hans Christian Andersen wrote a story called Under the Willow Tree (1853) in which children ask questions of a tree they call willow-father, paired with another entity called elder-mother.^[21]
• The Wind in the Willows
• Algernon Blackwood wrote a story called The Willows (1907) about two friends on a canoe trip down the Danube river who have a horrifying experience with the trees. This story was a personal favorite of H. P. Lovecraft.
• Green Willow is a Japanese ghost story in which a young samurai falls in love with a woman called Green Willow who has a close spiritual connection with a willow tree.^[22] The Willow Wife is another, not dissimilar tale.^[23] Wisdom of the Willow Tree is an Osage Nation story in which a young man seeks answers from a Willow tree, addressing the tree in conversation as 'Grandfather'.^[24]
• In J. K. Rowling's Harry Potter and the Chamber of Secrets, and Harry Potter and the Prisoner of Azkaban, there is an old tree on the school grounds of Hogwarts called the "Whomping Willow". It was planted in order to conceal a secret passageway that Professor Remus Lupin roamed through every full moon when he began his transformation into a werewolf.
• In William Shakespeare's Hamlet, the character Ophelia climbed a willow tree when a branch broke and dropped her into the river below where she drowned. In Shakespeare's "Twelfth Night", Viola (disguised as Cesario) tells Olivia "Make me a willow-cabin at your gate/ And call upon my soul within the house." The willow here being an emblem of forsaken love. In Shakespeare's Othello, Desdemona's song before her death uses the willow imagery to highlight her lost love.
• J. R. R. Tolkien's The Lord of the Rings also features a character known as Old Man Willow which traps some of Frodo's companions until they are rescued by Tom Bombadil.
• In Persian literature, the recognized adjective for 'willow' is lunatic (مجنون), and lover (or lovers' heart) is compared to willow in many texts.
• The willow is the symbol of wisdom. This is very clear in Disney's Pocahontas, in which Pocahontas asks the counsel of grandmother Willow.

Main species

The genus "Salix" is made up of around 400 species^[2] of deciduous trees and shrubs:

• Salix acutifolia Willd. – Long-leaved Violet Willow
• Salix aegyptiaca L.
• Salix alaxensis (Andersson) Coville
• Salix alba L. – White Willow
• Salix amplexicaulis Bory & Chaub.
• Salix amygdaloides Andersson – Peachleaf Willow
• Salix ansoniana J. Forbes
• Salix apennina A. K. Skvortsov
• Salix apoda Trautv.
• Salix appendiculata Vill.
• Salix arbuscula L.
• Salix arctica Pall. – Arctic Willow
• Salix argyracea E. L. Wolf
• Salix arizonica Dorn
• Salix armenorossica A. K. Skvortsov
• Salix atrocinerea Brot. – Grey Willow
• Salix aurita L. – Eared Willow
• Salix babylonica L. – Babylon Willow or Peking Willow
• Salix balfouriana C. K. Schneid.
• Salix barclayi Andersson
• Salix bebbiana Sarg. – Beaked Willow, Long-beaked Willow, and Bebb's Willow
• Salix bicolor Willd.
• Salix bikouensis Y. L. Chou
• Salix bonplandiana Kunth – Bonpland Willow
• Salix boothii Dorn – Booth's Willow
• Salix brachycarpa Nutt.
• Salix breviserrata Flod.
• Salix breweri Bebb – Brewer's Willow
• Salix burqinensis Chang Y. Yang
• Salix caesia Vill.
• Salix calcicola Fern. & Wieg. – Limestone Willow
• Salix calliantha J.Kern.
• Salix canariensis Chr. Sm.
• Salix candida Flüggé ex Willd. – Sageleaf Willow
• Salix cantabrica Rech. f.
• Salix capensis Thunb.
• Salix capitata Y. L. Chou & Skvortsov
• Salix caprea L. – Goat Willow or Pussy Willow
• Salix capusii Franch.
• Salix carmanica Bornm.
• Salix caroliniana Michx. – Coastal Plain Willow
• Salix caspica Pall.
• Salix cavaleriei H. Lév.
• Salix chaenomeloides Kimura
• Salix cinerea L. – Grey Willow
• Salix cordata Michx. – Sand Dune Willow, Furry Willow, or Heartleaf Willow
• Salix delnortensis C.K.Schneid. – Del Norte Willow
• Salix discolor Muhl. – American Willow
• Salix drummondiana Barratt ex Hook. – Drummond's Willow
• Salix eastwoodiae Cockerell ex A.Heller – Eastwood's Willow, Mountain Willow, or Sierra Willow
• Salix eriocephala Michx.
• Salix excelsa S. G. Gmel.
• Salix exigua Nutt. – Sandbar Willow, Narrowleaf Willow, or Coyote Willow
• Salix fargesii Burkill
• Salix floderusii Nakai
• Salix fluviatilis Nutt.
• Salix foetida Schleich. ex DC.
• Salix fragilis L. – Crack Willow
• Salix geyeriana Andersson – Geyer's Willow
• Salix gilgiana Seemen
• Salix glabra Scop.
• Salix glauca L.
• Salix glaucosericea Flod.
• Salix gooddingii C. R. Ball – Goodding's Willow, or Goodding's Black Willow
• Salix gordejevii Y. L. Chang & Skvortsov
• Salix graciliglans Nakai
• Salix gracilistyla Miq.
• Salix hastata L.
• Salix hegetschweileri Heer
• Salix helvetica Vill.
• Salix herbacea L. – Dwarf Willow, Least Willow or Snowbed Willow
• Salix hookeriana Barratt ex Hook. – Dune Willow, Coastal Willow, or Hooker's Willow
• Salix humboldtiana Willd.
• Salix humilis Marshall
• Salix hylematica C. K. Schneid.
• Salix integra Thunb.
• Salix irrorata Andersson
• Salix japonica Thunb.
• Salix jejuna Fernald – Barrens Willow
• Salix jepsonii C.K.Schneid. – Jepson's Willow
• Salix jessoensis Seemen
• Salix koreensis Andersson
• Salix koriyanagi Kimura ex Goerz
• Salix laevigata Bebb – Red Willow or Polished Willow
• Salix lanata L. – Woolly Willow
• Salix lapponum L.
• Salix lasiolepis Benth. – Arroyo Willow
• Salix lemmonii Bebb – Lemmon's Willow
• Salix ligulifolia C.R.Ball – Strapleaf Willow
• Salix linearistipularis (Franch.) K. S. Hao
• Salix longiflora Andersson
• Salix longistamina Z. Wang & P. Y. Fu
• Salix lucida Muhl. – Shining Willow, Pacific Willow, or Whiplash Willow
• Salix lutea Nutt. – Yellow Willow
• Salix magnifica Hemsl.
• Salix matsudana Koidz. – Chinese Willow
• Salix maximowiczii Kom.
• Salix medwedewii Dode
• Salix melanopsis Nutt. – Dusky Willow
• Salix microstachya Turcz.
• Salix mielichhoferi Saut.
• Salix miyabeana Seemen
• Salix moupinensis Franch.
• Salix mucronata - Cape Silver Willow
• Salix muscina Dode ex Flod.
• Salix myricoides Muhl.
• Salix myrsinifolia Salisb.
• Salix myrsinites L.
• Salix myrtilloides L. – Swamp Willow
• Salix neowilsonii W. P. Fang
• Salix nigra Marshall – Black Willow
• Salix nivalis Hook.
• Salix orestera C.K.Schneid. – Sierra Willow or Gray-leafed Sierra Willow
• Salix paraplesia C. K. Schneid.
• Salix pauciflora Koidz.
• Salix pedicellata Desf.
• Salix pellita Andersson
• Salix pentandra L. – Bay Willow
• Salix petiolaris Sm.
• Salix phlebophylla Andersson
• Salix phylicifolia L.
• Salix planifolia Pursh. – Diamondleaf Willow or Tea-leafed Willow
• Salix polaris Wahlenb. – Polar Willow
• Salix prolixa Andersson – MacKenzie's Willow
• Salix purpurea L. – Purple Willow or Purple Osier
• Salix pyrenaica Gouan
• Salix pyrifolia Andersson
• Salix pyrolifolia Ledeb.
• Salix rehderiana C. K. Schneid.
• Salix repens L.
• Salix reptans Rupr.
• Salix reticulata L. – Net-veined Willow
• Salix retusa L.
• Salix retusoides J.Kern.
• Salix rorida Lacksch.
• Salix rosmarinifolia L.
• Salix sajanensis Nasarow
• Salix salviifolia Brot.
• Salix schwerinii E. L. Wolf
• Salix scouleriana Barratt ex Hook. – Scouler's Willow
• Salix sericea Marshall – Silky Willow
• Salix serissima (L. H. Bailey) Fernald
• Salix serpyllifolia Scop.
• Salix sessilifolia Nutt. – Northwest Sandbar Willow
• Salix sitchensis C. A. Sanson ex Bong. – Sitka Willow
• Salix siuzevii Seemen
• Salix starkeana Willd.
• Salix subopposita Miq.
• Salix subserrata Willd.
• Salix suchowensis W. C. Cheng
• Salix sungkianica Y. L. Chou & Skvortsov
• Salix taxifolia Kunth – Yew-leaf Willow
• Salix tenuijulis Ledeb.
• Salix tetrasperma Roxb. – Indian Willow
• Salix triandra L. – Almond Willow or Almond-leaved Willow
• Salix turanica Nasarow
• Salix turfacea G. Haller ex Münchh.
• Salix udensis Trautv. & C. A. Mey.
• Salix uva-ursi Pursh. – Bearberry Willow
• Salix variegata Franch.
• Salix vestita Pursh. – Silky Willow
• Salix viminalis L. – Common Osier
• Salix vulpina Andersson
• Salix waldsteiniana Willd.
• Salix wallichiana Andersson
• Salix wilhelmsiana M. Bieb.
• Salix wilsonii Seemen
• Salix yezoalpina Koidz.

See also

Trees portal

• Aravah, the Hebrew name of the willow, for its ritual use during the Jewish Feast of Tabernacles
• List of Lepidoptera that feed on willows
• Rhabdophaga rosaria, a Willow gall

References

1. ^ "Genus Salix (willows)". Taxonomy. UniProt. http://www.uniprot.org/taxonomy/40685. Retrieved 2010-02-04. 
2. ^ ^{a b c} Mabberley, D.J. 1997. The Plant Book. Cambridge University Press #2: Cambridge.
3. ^ Hone, William (1826). "August 9". The Every-Day Book (Electronic Edition). http://www.uab.edu/english/hone/etexts/edb/day-pages/221-aug09.html.  Hone quotes "Martyn", and notes that Martyn in turn cites "the St. James's Chronicle, for August, 1801".
4. ^ Albury/Wodonga Willow Management Working Group (December 1998). "Willows along watercourses: managing, removing and replacing". Department of Primary Industries, State Government of Victoria. http://www.dse.vic.gov.au/dpi/nreninf.nsf/childdocs/-1C62D26CD3AF6FE44A2568B300051289-8E21A59E53B35BEFCA256BC80005C14F-E1EB709D7DCE1BC9CA256F070003E8D8-FAC3FFA202EA6384CA256BCF000AD522?open. 
5. ^ Cremer, Kurt W. (2003). "Introduced willows can become invasive pests in Australia" (PDF). http://www.hoadley.net/cremer/willows/docs/WillowInBiodiversity.pdf. 
6. ^ Salix spp. UFL/edu, Weeping Willow Fact Sheet ST-576, Edward F. Gilman and Dennis G. Watson, United States Forest Service
7. ^ "Rooting Around: Tree Roots", Dave Hanson, Yard & Garden Line News Volume 5 Number 15, University of Minnesota Extension, October 1, 2003
8. ^ James Breasted (English translation). "The Edwin Smith Papyrus". http://www.touregypt.net/edwinsmithsurgical.htm. Retrieved 2007-06-09. 
9. ^ "An aspirin a day keeps the doctor at bay: The world's first blockbuster drug is a hundred years old this week". http://www.nobelprizes.com/nobel/medicine/aspirin.html. Retrieved 2007-06-09. 
10. ^ W. Hale White. "Materia Medica Pharmacy, Pharmacology and Therapeutics". http://chestofbooks.com/health/materia-medica-drugs/Pharmacy-Pharmacology-And-Therapeutics/Salicinum-Salicin-Willow.html. Retrieved 2011-04-02. 
11. ^ Hageneder, Fred (2001). The Heritage of Trees. Edinburgh : Floris. ISBN 0-86315-359-3. p.172
12. ^ Aylott, Matthew J.; Casella, E; Tubby, I; Street, NR; Smith, P; Taylor, G (2008). "Yield and spatial supply of bioenergy poplar and willow short-rotation coppice in the UK" (PDF). New Phytologist 178 (2): 358–370. doi:10.1111/j.1469-8137.2008.02396.x. PMID 18331429. http://www3.interscience.wiley.com/journal/119394739/abstract. Retrieved 2008-10-22. 
13. ^ Mola-Yudego, Blas; Aronsson, Pär. (2008). "Yield models for commercial willow biomass plantations in Sweden" (PDF). Biomass and Bioenergy 32 (9): 829–837. doi:10.1016/j.biombioe.2008.01.002. http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V22-4S02D5N-1&_user=949127&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1102089875&_rerunOrigin=google&_acct=C000049117&_version=1&_urlVersion=0&_userid=949127&md5=9a3b80e6d4a86a87261094ef833dee16. Retrieved 2009-11-20. 
14. ^ Forestresearch.gov.uk
15. ^ ChurchYear.net
16. ^ Doolittle, Justus (2002) [1876]. Social Life of the Chinese. Routledge. ISBN 9780710307538. 
17. ^ Doré S.J., Henry; Kennelly, S.J. (Translator), M. (1914). Researches into Chinese Superstitions. Tusewei Press, Shanghai.  Vol I p. 2
18. ^ "The Forest of Willows in Our Minds". Arirang TV. August 20, 2007. Retrieved September 10, 2007. http://www.arirang.co.kr/Tv/TSymbols_Archive.asp?PROG_CODE=TVCR0271&view_cont_seq=4&code=St1&sys_lang=Eng. 
19. ^ "In Worship of Trees by George Knowles: Willow". http://www.controverscial.com/Willow.htm. 
20. ^ "Mythology and Folklore of the Willow". http://www.treesforlife.org.uk/forest/mythfolk/willow.html. 
21. ^ Under The Willow Tree
22. ^ Green Willow
23. ^ The Willow Wife
24. ^ Wisdom of the Willow Tree

Bibliography

• Keeler, Harriet L. (1990). Our Native Trees and How to Identify Them. New York: Charles Scriber's Sons. Pages 393–395. ISBN 0873388380.
• Newsholme, C. (1992). Willows: The Genus Salix. ISBN 0-88192-565-9
• Warren-Wren, S.C. (1992). The Complete Book of Willows. ISBN 0-498-01262-X
• Sviatlana Trybush, Šárka Jahodová, William Macalpine and Angela Karp. (2008). A genetic study of a Salix germplasm resource reveals new insights into relationships among subgenera, sections and species BioEnergy Research. 1(1):67 – 79.

External links

• Salix alba at plants for a future
• Salix purpurea at plants for a future
• 1911 Encyclopaedia Britannica
• Salix caroliniana images at bioimages.vanderbilt.edu
• Salix nigra images at bioimages.vanderbilt.edu
• Weeping Willow - Salix alba Diagnostic photos, Morton Arboretum specimens
• Willow Cuttings