Tilia is agenus of about 30 species of trees or bushes, native throughout most of thetemperate Northern Hemisphere. The species are known aslinden orlime for the European and Asian species,[2][3] andlinden orbasswood for North American species and more generally inAmerican literature.[4][5] The greatest species diversity is found in Asia, but the genus also occurs widely in Europe and eastern North America. Under theCronquist classification system, this genus was placed in the familyTiliaceae, but genetic research summarised by theAngiosperm Phylogeny Group has resulted in the incorporation of this genus, and of most of the previous family, into theMalvaceae.
Tilia is the only knownectomycorrhizal genus in the familyMalvaceae. Studies of ectomycorrhizal relations ofTilia species indicate a wide range of fungal symbionts and a preference towardAscomycota fungal partners.[6][7][8]
Tilia species are mostly large,deciduous trees, reaching typically 20 to 40 m (65 to 130 ft) tall. As withelms, the exact number of species is uncertain, as many of the species canhybridise readily, both in the wild and in cultivation. They arehermaphroditic, havingperfect flowers with both male and female parts, pollinated by insects.
The trunk is stout, with pale grey to brownish-grey bark, smooth at first, becoming coarsely fissured or scaly on older trees; the inner bark, called bast, is soft, but fibrous, with high tensile strength. The wood is white, fairly soft, with minimal wood grain, making it popular for wood carving (see #Wood below).
The leaves ofTilia species are heart-shaped, and most are asymmetrical, with oblique-cordate (heart-shaped) leaves 4 to 20 cm (1+1⁄2 to7+3⁄4 in) across, sometimes more, to 25 cm in the hybrid cultivarTilia 'Moltkei'.[9] In all species, the leaf margin is toothed, sometimes markedly so, withT. henryana having conspicuous long bristle-like teeth up to 4.4 mm long.[3] In another species,T. mongolica, the leaves are also distinctly three- to five-lobed as one or two pairs of the marginal teeth are larger than the others; in this species, the leaf base is also usually symmetrical, not oblique as in other limes.[3]
The flowers are small (10–15 mm diameter) and symmetrical, with five sepals and five petals; the petals are yellow to greenish-yellow, about twice the length of the sepals when fully open; they are strongly scented, and very attractive to bees and other insects.[3] The flowers of European and AmericanTilia species are similar, except the American ones bear a petal-like scale among their stamens and the European species are devoid of these appendages.[citation needed] The tiny, pea-sized fruit hangs attached to a ribbon-like, greenish-yellowbract whose apparent purpose is to aid the ripened seed clusters to blow in wind to a little beyond the parent tree. The fruit is mostly smooth and variably downy, but inT. chinensis andT. platyphyllos is prominently ribbed, with five ribs.[10] All of theTilia species may be propagated by cuttings and grafting, as well as by seed. They grow rapidly in rich soil, but are subject to damage by several insects.Tilia is notoriously difficult to propagate from seed unless collected fresh in autumn; if allowed to dry, the seeds go into deep dormancy and take 18 months to germinate.[11]
Bole of an ancientTilia at Frankenbrunn,BavariaAncient lime tree atChilston Park, EnglandAvenue of lime trees at Turville HeathTilia in theMünzenberg Castle
The genus is generally called "lime" in Britain[12] and "linden", or "basswood" in North America.[5]
"Lime" is an altered form ofMiddle Englishlind, in the 16th century alsoline, from Old English femininelind orlinde,Proto-Germanic*lindō (cf. Dutch[13]/GermanLinde, pluralLinden), cognate to Latinlentus "flexible" and Sanskritlatā "liana". WithinGermanic languages, English "lithe" and Dutch[14]/Germanlind for "lenient, yielding" are from the same root.
"Linden" was originally the adjective, "made from linwood or lime-wood" (equivalent to "wooden" or "oaken"); from the late 16th century, "linden" was also used as a noun, probably influenced by translations of German romance, as an adoption ofLinden, the plural ofLinde in Dutch[13] and German.[citation needed]Neither the name nor the tree is related toCitrus genus species and hybrids that go by the same name, such asKey limes (Citrus × aurantifolia). Another common name used in North America is basswood, derived frombast, the name for the inner bark (seeUses, below).Teil is an old name for the lime tree.
Aphids are attracted by the rich supply of sap, and are in turn often "farmed" by ants for the production of the honeydew (an aphid waste product), which the ants collect for their own use, and the result can often be a dripping of excess sap onto the lower branches and leaves, and anything else below. Cars left under the trees can quickly become coated with a film of the syrup ("honeydew") thus dropped from higher up. The ant/aphid "farming" process does not appear to cause any serious damage to the trees.[15]
Limes are widely used as ornamental trees when a mass of foliage or a deep shade is desired.[11] It produces fragrant and nectar-producing flowers and is an important honey plant for beekeepers, giving rise to a pale but richly flavouredmonofloral honey. In European and North American herbal medicine, the flowers are also used for herbal teas andtinctures. The flowers are used for herbal tea in the winter in the Balkans. In China, driedTilia flowers are also used to make tea.[16]
InEnglish landscape gardens, avenues of linden trees were fashionable, especially during the late 17th and early 18th centuries. Manycountry houses have a surviving "lime avenue" or "lime walk", the example atHatfield House was planted between 1700 and 1730.[17] The fashion was derived from the earlier practice of planting lindens in lines as shade trees in Germany, the Netherlands, Belgium, and northern France. Most of the trees used in British gardens werecultivars propagated bylayering in the Netherlands.[18]
Linden trees produce soft and easily worked timber, which has very littlegrain and a density of 560 kg/m3.[19] It was often used by Germanic tribes for constructing shields. It is a popular wood for model building and for intricate carving. Especially in Germany, it was the classic wood for sculpture from the Middle Ages onwards and is the material for the elaboratealtarpieces ofVeit Stoss,Tilman Riemenschneider, and many others. In England, it was the favoured medium of sculptorGrinling Gibbons[20] (1648–1721). The wood is used inmarionette- andpuppet-making and -carving. Having a fine, light grain and being comparatively light in weight, it has been used for centuries for this purpose; despite the availability of modern alternatives, it remains one of the main materials used as of 2015[update]. In China, it was also widely used in carving or furniture, interior decorating, handicrafts, etc.[16]
Ease of working and good acoustic properties also make limewood popular for electric and bass guitar bodies and forwind instruments such asrecorders.Percussion manufacturers sometimes useTilia as a material for drum shells, both to enhance their sound and for their aesthetics.[citation needed]
Linden wood is also the material of choice for window blinds and shutters. Real-wood blinds are often made from this lightweight but strong and stable wood, which is well suited to natural and stained finishes.[citation needed]
In China,冻蘑/"dongmo" grows well on decomposing logs ofTilia trees in theold-growth forest;[16] therefore, people use logs ofTilia trees to cultivateS. edulis and evenblack fungus orshiitake mushrooms with excellent results. Currently, "椴木黑木耳/Tilia-logs-black fungus" or "椴木香菇/Tilia-logs-shiitake mushrooms" has become a term for a method of cultivating black fungus and shiitake mushrooms and "椴木/Tilia-logs" no longer exclusively refers toTilia tree wood but also to other woods suitable for black fungus or shiitake mushrooms cultivation.[21]
In Russian, "linden-made" (липовый,lipoviy) is a term for forgery, due to the popularity of the material for making forged seals in the past centuries.[22]
Known in the trade as basswood, particularly in North America, its name originates from the inner fibrous bark of the tree, known as bast. A strong[23]fibre is obtained from the tree by peeling off the bark and soaking it in water for a month, after which the inner fibres can be easily separated. Bast obtained from the inside of the bark of theTilia japonica tree has been used by theAinu people of Japan to weave their traditional clothing, theattus. Excavations in Britain have shown that lime tree fibre was preferred for clothing there during the Bronze Age.[24] TheManchu people in the mountains of Northeast China made ropes, baskets, raincoats, large fishing nets, and guide lines for gunpowder from the bast.[25] Similar fibres obtained from other plants are also called bast: seeBast fibre.
Tilia is a high-quality wild honey plant. In China, "椴树蜜/Tilia honey" is produced in the northeast region. White in color, it is called "white honey" or "snow honey".Heilongjiang is well-known throughout the country for producing high-quality "Tilia honey": Heilongjiang not only has lushTilia trees, but also a rare and excellent bee species - "东北黑蜂/northeast black bee" to collect honey（Raohe County is the location of the national "东北黑蜂自然保护区/Northeast Black Bee Nature Reserve". It is the only nature reserve for bees in Asia.[26]).[27] "Tilia honey" mainly comes fromTilia amurensis andTilia mandshurica.[27] "Tilia honey" and southern "longan honey" and "lychee honey" are called "China's three famous honeys".[16] "Tilia honey", "rape honey" and "black acacia honey" are the three most productive honeys in China.[28]
The dried flowers are mildly sweet and sticky, and the fruit is somewhat sweet and mucilaginous. Linden flower tea has a pleasing taste, due to the aromaticvolatile oil found in the flowers.Phytochemicals in theTilia flowers includeflavonoids andtannins withastringent properties.[29]
The nectar contains a major secondary metabolite with the trivial name tiliaside (1-[4-(1-hydroxy-1-methylethyl)-1,3-cyclohexadiene-1-carboxylate]-6-O-β-D-glucopyranosyl-β-D-glucopyranose), which is transformed in the gut ofbumblebees to the aglycone (i.e., the gentiobiose group is cleaved), which is bioactive against a common and debilitating gut parasite of bumblebees,Crithidia bombi. This naturally occurring compound may support bees to manage the burden of disease - one of the major contributors to pollinator decline.[30]
A beverage made from dried linden leaves and flowers is brewed and consumed as a folk medicine and relaxant in many Eastern European countries.[31] Usually, the double-flowered species are used to make perfumes.[citation needed] The leaf buds and young leaves are also edible raw.[32][33]
Tilia species are used as food plants by thelarvae of someLepidoptera; see List of Lepidoptera that feed onTilia.
In Europe, some linden trees reached considerable ages. Acoppice ofT. cordata inWestonbirt Arboretum inGloucestershire is estimated to be 2,000 years old.[34] In the courtyard of theImperial Castle at Nuremberg is aTilia, which by tradition recounted in 1900, was planted by theEmpress Cunigunde, the wife ofHenry II of Germanycirca 1000. TheTilia of Neuenstadt am Kocher in Baden-Württemberg, Germany, was estimated at 1000 years old when it fell.[11] The Alte Linde tree of Naters, Switzerland, is mentioned in a document in 1357 and described by the writer at that time as alreadymagnam (large). A plaque at its foot mentions that in 1155, a linden tree was already on this spot. TheNajevnik linden tree (Slovene:Najevska lipa), a 700-year-oldT. cordata, is the thickest tree inSlovenia.[35] Next to the 英華殿/Yinghua Temple in theForbidden City inBeijing, there are twoTilia trees planted by Empress Dowager Li, the biological mother ofWanli Emperor about five hundred years ago.[36]
The excellence of the honey of the far-famedHyblaean Mountains[37] was due to the linden trees that covered its sides and crowned its summit.
Lime fossils have been found in theTertiary formations ofGrinnell Land, Canada, at 82°N latitude, and inSvalbard, Norway. Sapporta believed he had found there the common ancestor of theTilia species of Europe and America.[11]
^Timonen, Sari; Kauppinen, Pauliina (January 2008). "Mycorrhizal colonisation patterns of Tilia trees in street, nursery and forest habitats in southern Finland".Urban Forestry & Urban Greening.7 (4):265–276.Bibcode:2008UFUG....7..265T.doi:10.1016/j.ufug.2008.08.001.
^Rudawska, Maria; Kujawska, Marta; Leski, Tomasz; Janowski, Daniel; Karliński, Leszek; Wilgan, Robin (April 2019). "Ectomycorrhizal community structure of the admixture tree species Betula pendula, Carpinus betulus, and Tilia cordata grown in bare-root forest nurseries".Forest Ecology and Management.437:113–125.Bibcode:2019ForEM.437..113R.doi:10.1016/j.foreco.2019.01.009.S2CID91789869.
^Šmid Hribar, Mateja."Najevska lipa" [Najevnik Linden Tree]. In Šmid Hribar, Mateja; Golež, Gregor; Podjed, Dan; Kladnik, Drago; Erhartič, Bojan; Pavlin, Primož; Ines, Jerele (eds.).Enciklopedija naravne in kulturne dediščine na Slovenskem – DEDI [Encyclopedia of Natural and Cultural Heritage in Slovenia] (in Slovenian). Retrieved28 August 2013.
^苏怡."英華殿" (in Chinese). The Palace Museum. Retrieved2023-01-12.
^"Honey".Encyclopædia Britannica (9th ed.). RetrievedNovember 22, 2011....honey most esteemed by the ancients was that of Mount Hybla in Sicily...
