71-415: Corymbia , commonly known as bloodwoods , is a genus of about one hundred species of tree that, along with Eucalyptus , Angophora and several smaller groups, are referred to as eucalypts . Until 1990, corymbias were included in the genus Eucalyptus and there is still considerable disagreement among botanists as to whether separating them is valid. As of January 2020, Corymbia is an accepted name at
142-554: A leaf base where the two sides of the leaf blade are of unequal length and do not meet the petiole at the same place. E. obliqua was published in 1788–89, which coincided with the European colonisation of Australia. Between then and the turn of the 19th century, several more species of Eucalyptus were named and published. Most of these were by the English botanist James Edward Smith and most were, as might be expected, trees of
213-537: A "cap" or operculum over the stamens , hence the name from Greek eû ("well") and kaluptós ("covered"). The fruit is a woody capsule commonly referred to as a "gumnut". Most species of Eucalyptus are native to Australia, and every state and territory has representative species. About three-quarters of Australian forests are eucalypt forests. Many eucalypt species have adapted to wildfire , are able to resprout after fire, or have seeds that survive fire. A few species are native to islands north of Australia, and
284-412: A better chance of recovery from damage sustained to its leaves in an event such as a fire. Different commonly recognised types of bark include: Nearly all Eucalyptus are evergreen , but some tropical species lose their leaves at the end of the dry season. As in other members of the myrtle family, Eucalyptus leaves are covered with oil glands. The copious oils produced are an important feature of
355-492: A branching peduncle , each branch usually with seven buds, but with the pedicels of differing lengths, so that the inflorescence is flat-topped or convex. The anthers are joined to the filament at their mid-point and open by parallel slits. As in Eucalyptus , the five sepals are fused to form an outer calyptra (or operculum ) and the five petals an inner calyptra, the two calyptra being shed separately or together as
426-570: A distinct group within the large and diverse genus Eucalyptus since 1867. Molecular research in the 1990s, however, showed that they, along with the rest of the section Corymbia, are more closely related to Angophora than to Eucalyptus , and are now regarded as a separate genus by the Australian Plant Census . All three genera, Angophora , Corymbia and Eucalyptus , are closely related, and are generally referred to as " eucalypts ". Botanists Ken Hill and Lawrie Johnson were
497-399: A dramatic increase in the abundance of Eucalyptus pollen are associated with increased charcoal levels. Though this occurs at different rates throughout Australia, it is compelling evidence for a relationship between the artificial increase of fire frequency with the arrival of Aboriginals and increased prevalence of this exceptionally fire-tolerant genus. Several eucalypt species are among
568-486: A grass fire is insufficient to ignite the scattered trees. In contrast, a Eucalyptus forest tends to promote fire because of the volatile and highly combustible oils produced by the leaves, as well as the production of large amounts of litter high in phenolics, preventing its breakdown by fungi and thus accumulating as large amounts of dry, combustible fuel. Consequently, dense eucalypt plantings may be subject to catastrophic firestorms. In fact, almost thirty years before
639-676: A natural insecticide , or an ability to be used to drain swamps and thereby reduce the risk of malaria . Eucalyptus oil finds many uses like in fuels, fragrances, insect repellence and antimicrobial activity. Eucalyptus trees show allelopathic effects; they release compounds which inhibit other plant species from growing nearby. Outside their natural ranges, eucalypts are both lauded for their beneficial economic impact on poor populations and criticised for being "water-guzzling" aliens , leading to controversy over their total impact. Myrtaceae About 130; see list Myrtaceae ( / m ə r ˈ t eɪ s i ˌ aɪ , - s iː ˌ iː / ),
710-468: A range of climates but are usually damaged by anything beyond a light frost of −5 °C (23 °F); the hardiest are the snow gums, such as Eucalyptus pauciflora , which is capable of withstanding cold and frost down to about −20 °C (−4 °F). Two subspecies, E. pauciflora subsp. niphophila and E. pauciflora subsp. debeuzevillei in particular are even hardier and can tolerate even quite severe winters. Several other species, especially from
781-640: A shrub or small tree with a single, short trunk, that lacks a lignotuber and has spreading, densely leafy branches that often reach almost to the ground. Eucalyptus platypus is an example of a marlock. Eucalyptus trees, including mallets and marlocks, are single-stemmed and include Eucalyptus regnans , the tallest known flowering plant on Earth. The tallest reliably measured tree in Europe, Karri Knight , can be found in Coimbra , Portugal in Vale de Canas. It
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#1732787171329852-464: A single main stem or trunk but many eucalypts are mallees that are multistemmed from ground level and rarely taller than 10 metres (33 feet). There is no clear distinction between a mallee and a shrub but in eucalypts, a shrub is a mature plant less than 1 m (3 ft 3 in) tall and growing in an extreme environment. Eucalyptus vernicosa in the Tasmanian highlands, E. yalatensis on
923-566: A small amount of ash survived and put out new ash trees as well. Eucalyptus oil is highly flammable and at high enough temperatures the oil expands quickening the spread of wildfires. Bushfires can travel easily through the oil-rich air of the tree crowns. Eucalypts obtain long-term fire survivability from their ability to regenerate from epicormic buds situated deep within their thick bark, or from lignotubers , or by producing serotinous fruits. In seasonally dry climates oaks are often fire-resistant, particularly in open grasslands, as
994-450: A smaller number are only found outside the continent. Eucalypts have been grown in plantations in many other countries because they are fast-growing, have valuable timber, or can be used for pulpwood , honey production, or essential oils . In some countries, however, they have been removed because of the danger of forest fires due to their high flammability. Eucalypts vary in size and habit from shrubs to tall trees. Trees usually have
1065-495: A toothed margin). The flowers have a base number of five petals, though in several genera, the petals are minute or absent. The stamens are usually very conspicuous, brightly coloured, and numerous. Scientists hypothesize that the family Myrtaceae arose between 60 and 56 million years ago (Mya) during the Paleocene era. Pollen fossils have been sourced to the ancient supercontinent Gondwana . The breakup of Gondwana during
1136-533: Is a Eucalyptus diversicolor of 72.9 meters height and of 5.71 meters girth. Tree sizes follow the convention of: All eucalypts add a layer of bark every year and the outermost layer dies. In about half of the species, the dead bark is shed exposing a new layer of fresh, living bark. The dead bark may be shed in large slabs, in ribbons or in small flakes. These species are known as "smooth barks" and include E. sheathiana , E. diversicolor , E. cosmophylla and E. cladocalyx . The remaining species retain
1207-720: Is almost three times as great as native oak woodland. During World War II , one California town cut down their Eucalyptus trees to "about a third of their height in the vicinity of anti-aircraft guns " because of the known fire-fueling qualities of the trees, with the mayor telling a newspaper reporter, "If a shell so much as hits a leaf, it's supposed to explode." Some species of Eucalyptus drop branches unexpectedly. In Australia, Parks Victoria warns campers not to camp under river red gums . Some councils in Australia such as Gosnells, Western Australia , have removed eucalypts after reports of damage from dropped branches, even in
1278-513: Is also used in a number of industries, from fence posts (where the oil-rich wood's high resistance to decay is valued) and charcoal to cellulose extraction for biofuels . Fast growth also makes eucalypts suitable as windbreaks and to reduce erosion . Some Eucalyptus species have attracted attention from horticulturists, global development researchers, and environmentalists because of desirable traits such as being fast-growing sources of wood, producing oil that can be used for cleaning and as
1349-691: Is constrained by their limited cold tolerance. Australia is covered by 92,000,000 hectares (230,000,000 acres) of eucalypt forest, comprising three quarters of the area covered by native forest. The Blue Mountains of southeastern Australia have been a centre of eucalypt diversification; their name is in reference to the blue haze prevalent in the area, believed derived from the volatile terpenoids emitted by these trees. The oldest definitive Eucalyptus fossils are from Patagonia in South America , where eucalypts are no longer native, though they have been introduced from Australia. The fossils are from
1420-698: Is high due to its high resin content, increasing the hazard. Eucalypts were introduced from Australia to the rest of the world following the Cook expedition in 1770. Collected by Sir Joseph Banks , botanist on the expedition, they were subsequently introduced to many parts of the world, notably California , southern Europe, Africa, the Middle East , South Asia and South America. About 250 species are under cultivation in California. In Portugal and also Spain , eucalypts have been grown in plantations for
1491-452: Is useful to consider where Eucalyptus fossils have not been found. Extensive research has gone into the fossil floras of the Paleocene to Oligocene of South-Eastern Australia, and has failed to uncover a single Eucalyptus specimen. Although the evidence is sparse, the best hypothesis is that in the mid-Tertiary, the continental margins of Australia only supported more mesic noneucalypt vegetation, and that eucalypts probably contributed to
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#17327871713291562-445: The Australian Plant Census . Eucalypts in the genus Corymbia are trees, sometimes mallee -like, that either have rough, fibrous or flaky bark, or smooth bark that is shed in small flakes or short strips. Young plants and coppice regrowth have leaves that differ from adult leaves. The adult leaves are arranged alternately (strictly disjunct opposite, but appearing alternate), with oil glands. The flower buds are arranged in groups on
1633-590: The Cretaceous period (145 to 66 Mya) geographically isolated disjunct taxa and allowed for rapid speciation; in particular, genera once considered members of the now-defunct Leptospermoideae alliance are now isolated within Oceania . Generally, experts agree that vicariance is responsible for the differentiation of Myrtaceae taxa, except in the cases of Leptospermum species now located on New Zealand and New Caledonia , islands which may have been submerged at
1704-684: The Endeavour River in northern Queensland , E. platyphylla ; neither of these species was named as such at the time. In 1777, on Cook's third expedition, David Nelson collected a eucalypt on Bruny Island in southern Tasmania . This specimen was taken to the British Museum in London , and was named Eucalyptus obliqua by the French botanist L'Héritier , who was working in London at
1775-524: The Nullarbor and E. surgens growing on coastal cliffs in Western Australia are examples of eucalypt shrubs. The terms " mallet " and " marlock " are only applied to Western Australian eucalypts. A mallet is a tree with a single thin trunk with a steeply branching habit but lacks both a lignotuber and epicormic buds . Eucalyptus astringens is an example of a mallet. A marlock is
1846-546: The Oakland firestorm of 1991 , a study of Eucalyptus in the area warned that the litter beneath the trees builds up very rapidly and should be regularly monitored and removed. It has been estimated that 70% of the energy released through the combustion of vegetation in the Oakland fire was due to Eucalyptus . In a National Park Service study, it was found that the fuel load (in tons per acre) of non-native Eucalyptus woods
1917-497: The Peruvian Andes , despite concerns that the trees are invasive in some environments like those of South Africa . Best-known are perhaps the varieties karri and yellow box . Due to their fast growth, the foremost benefit of these trees is their wood. They can be chopped off at the root and grow back again. They provide many desirable characteristics for use as ornament , timber, firewood and pulpwood. Eucalyptus wood
1988-636: The Philippines . Of the 15 species found outside Australia, just nine are exclusively non-Australian. Species of Eucalyptus are cultivated widely in the tropical and temperate world, including the Americas , Europe , Africa , the Mediterranean Basin , the Middle East , China , and the Indian subcontinent . However, the range over which many eucalypts can be planted in the temperate zone
2059-656: The Sydney region. These include the economically valuable E. pilularis , E. saligna and E. tereticornis . The first endemic Western Australian Eucalyptus to be collected and subsequently named was the Yate ( E. cornuta ) by the French botanist Jacques Labillardière , who collected in what is now the Esperance area in 1792. Several Australian botanists were active during the 19th century, particularly Ferdinand von Mueller , whose work on eucalypts contributed greatly to
2130-498: The bark (e.g., scribbly gum ). The generic name is derived from the Greek words ευ ( eu ) "well" and καλύπτω ( kalýpto ) "to cover", referring to the operculum on the calyx that initially conceals the flower . There are more than 700 species of Eucalyptus and most are native to Australia; a very small number are found in adjacent areas of New Guinea and Indonesia . One species, Eucalyptus deglupta , ranges as far north as
2201-444: The myrtle family , is a family of dicotyledonous plants placed within the order Myrtales . Myrtle , pōhutukawa , bay rum tree , clove , guava , acca (feijoa) , allspice , and eucalyptus are some notable members of this group. All species are woody, contain essential oils , and have flower parts in multiples of four or five. The leaves are evergreen , alternate to mostly opposite, simple, and usually entire (i.e., without
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2272-703: The tallest trees in the world. Eucalyptus regnans , the Australian 'mountain ash', is the tallest of all flowering plants ( angiosperms ); today, the tallest measured specimen named Centurion is 100.5 m (330 ft) tall. Coast Douglas-fir is about the same height; only coast redwood is taller, and they are conifers ( gymnosperms ). Six other eucalypt species exceed 80 metres in height: Eucalyptus obliqua , Eucalyptus delegatensis , Eucalyptus diversicolor , Eucalyptus nitens , Eucalyptus globulus and Eucalyptus viminalis . Most eucalypts are not tolerant of severe cold. Eucalypts do well in
2343-640: The Americas, apart from Metrosideros in Chile and Argentina . Genera with fleshy fruits have their greatest concentrations in eastern Australia and Malesia (the Australasian realm ) and the Neotropics . Eucalyptus is a dominant, nearly ubiquitous genus in the more mesic parts of Australia and extends north sporadically to the Philippines . Eucalyptus regnans is the tallest flowering plant in
2414-405: The arrangement reverts to decussate by the absorption of some of the leaf-bearing faces of the stem. In those species with opposite adult foliage the leaf pairs, which have been formed opposite at the stem apex, become separated at their bases by unequal elongation of the stem to produce the apparently alternate adult leaves. The most readily recognisable characteristics of Eucalyptus species are
2485-575: The baccate (fleshy) fruits evolved twice from capsular fruits and, as such, the two-subfamily classification does not accurately portray the phylogenetic history of the family. Thus, many workers are now using a recent analysis by Wilson et al. (2001) as a starting point for further analyses of the family. This study pronounced both Leptospermoideae and Myrtoideae invalid, but retained several smaller suballiances shown to be monophyletic through matK analysis. The genera Heteropyxis and Psiloxylon have been separated as separate families by many authors in
2556-1052: The characteristics of buds, fruits, leaves and bark. Over 700 species of Eucalyptus are known. Some have diverged from the mainstream of the genus to the extent that they are quite isolated genetically and are able to be recognised by only a few relatively invariant characteristics. Most, however, may be regarded as belonging to large or small groups of related species, which are often in geographical contact with each other and between which gene exchange still occurs. In these situations, many species appear to grade into one another, and intermediate forms are common. In other words, some species are relatively fixed genetically, as expressed in their morphology , while others have not diverged completely from their nearest relatives. Hybrid individuals have not always been recognised as such on first collection and some have been named as new species, such as E. chrysantha ( E. preissiana × E. sepulcralis ) and E. "rivalis" ( E. marginata × E. megacarpa ). Hybrid combinations are not particularly common in
2627-426: The cup-like base of the flower; this is one of the features that unites the genus. The woody fruits or capsules are roughly cone-shaped and have valves at the end which open to release the seeds, which are waxy, rod-shaped, about 1 mm in length, and yellow-brown in colour. Most species do not flower until adult foliage starts to appear; E. cinerea and E. perriniana are notable exceptions. The genus Eucalyptus
2698-424: The dead bark is retained in the lower half of the trunks or stems—for example, E. brachycalyx , E. ochrophloia , and E. occidentalis —or only in a thick, black accumulation at the base, as in E. clelandii . In some species in this category, for example E. youngiana and E. viminalis , the rough basal bark is very ribbony at the top, where it gives way to the smooth upper stems. The smooth upper bark of
2769-452: The dead bark which dries out and accumulates. In some of these species, the fibres in the bark are loosely intertwined (in stringybarks such as E. macrorhyncha or peppermints such as E. radiata ) or more tightly adherent (as in the "boxes" such as E. leptophleba ). In some species (the "ironbarks" such as E. crebra and E. jensenii ) the rough bark is infused with gum resin. Many species are 'half-barks' or 'blackbutts' in which
2840-433: The distinctive flowers and fruit (capsules or "gumnuts"). Flowers have numerous fluffy stamens which may be white, cream, yellow, pink, or red; in bud, the stamens are enclosed in a cap known as an operculum which is composed of the fused sepals or petals, or both. Thus, flowers have no petals, but instead decorate themselves with the many showy stamens. As the stamens expand, the operculum is forced off, splitting away from
2911-475: The drier vegetation of the arid continental interior. With the progressive drying out of the continent since the Miocene , eucalypts were displaced to the continental margins, and much of the mesic and rainforest vegetation that was once there was eliminated. The current superdominance of Eucalyptus in Australia may be an artefact of human influence on its ecology. In more recent sediments, numerous findings of
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2982-643: The early Eocene (51.9 Mya), and were found in the Laguna del Hunco Formation in Chubut Province in Argentina . This shows that the genus had a Gondwanan distribution. Fossil leaves also occur in the Miocene of New Zealand, where the genus is not native today, but again have been introduced from Australia. Despite the prominence of Eucalyptus in modern Australia, estimated to contribute some 75% of
3053-500: The face of lengthy, well publicised protests to protect particular trees. A former Australian National Botanic Gardens director and consulting arborist, Robert Boden, has been quoted referring to "summer branch drop". Dropping of branches is recognised in Australia literature through the fictional death of Judy in Seven Little Australians . Although all large trees can drop branches, the density of Eucalyptus wood
3124-430: The family Myrtaceae . Most species of Eucalyptus are trees, often mallees , and a few are shrubs. Along with several other genera in the tribe Eucalypteae , including Corymbia and Angophora , they are commonly known as eucalypts or "gum trees". Plants in the genus Eucalyptus have bark that is either smooth, fibrous, hard, or stringy and leaves that have oil glands . The sepals and petals are fused to form
3195-406: The field, but some other published species frequently seen in Australia have been suggested to be hybrid combinations. For example, Eucalyptus × erythrandra is believed to be E. angulosa × E. teraptera and due to its wide distribution is often referred to in texts. Renantherin , a phenolic compound present in the leaves of some Eucalyptus species, allows chemotaxonomic discrimination in
3266-589: The first comprehensive account of the genus in George Bentham 's Flora Australiensis in 1867. The account is the most important early systematic treatment of the genus. Bentham divided it into five series whose distinctions were based on characteristics of the stamens, particularly the anthers (Mueller, 1879–84), work elaborated by Joseph Henry Maiden (1903–33) and still further by William Faris Blakely (1934). The anther system became too complex to be workable and more recent systematic work has concentrated on
3337-508: The first to define the genus Corymbia in 1995, identifying the bloodwoods, ghost gums and spotted gums as a group distinct from Eucalyptus . Since 1995, there have been ongoing investigations into the relationships between the genera. Genetic analysis of ETS and ITS sequences of DNA in 2006 by Carlos Parra-O and colleagues of 67 taxa (47 of which were within Corymbia ) yielded Corymbia and Angophora as each other's closest relatives, with
3408-627: The flower buds. The type specimen was collected in 1777 by David Nelson , the gardener-botanist on Cook's third voyage . He collected the specimen on Bruny Island and sent it to de Brutelle who was working in London at that time. Although eucalypts must have been seen by the very early European explorers and collectors, no botanical collections of them are known to have been made until 1770 when Joseph Banks and Daniel Solander arrived at Botany Bay with Captain James Cook . There they collected specimens of E. gummifera and later, near
3479-504: The flower opens. Also as in Eucalyptus the fruit is usually a woody capsule , but in this case the disc is always depressed and the valves are always enclosed. The genus Corymbia was first formally described in 1995 by Ken Hill and Lawrie Johnson in the journal Telopea . The type species is C. gummifera . The genus name, Corymbia is from the Latin word corymbus , meaning "a corymb ". The bloodwoods had been recognised as
3550-412: The genus Eucalyptus as an earlier offshoot. The small genera Eucalyptopsis , Stockwellia and Allosyncarpia formed a clade which arose earlier still. In 2009, Parra-O and colleagues added more taxa and published a combined analysis of nuclear rDNA (ETS + ITS) and morphological characters published to clarify relationships within the genus. This confirmed two main clades, which they defined as
3621-489: The genus. Although mature Eucalyptus trees may be towering and fully leafed, their shade is characteristically patchy because the leaves usually hang downwards. The leaves on a mature Eucalyptus plant are commonly lanceolate , petiolate , apparently alternate and waxy or glossy green. In contrast, the leaves of seedlings are often opposite , sessile and glaucous . But many exceptions to this pattern exist. Many species such as E. melanophloia and E. setosa retain
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#17327871713293692-408: The half-barks and that of the completely smooth-barked trees and mallees can produce remarkable colour and interest, for example E. deglupta . E. globulus bark cells are able to photosynthesize in the absence of foliage, conferring an "increased capacity to re-fix internal CO 2 following partial defoliation". This allows the tree to grow in less-than-ideal climates, in addition to providing
3763-799: The high plateau and mountains of central Tasmania such as Eucalyptus coccifera , Eucalyptus subcrenulata and Eucalyptus gunnii , have also produced extreme cold-hardy forms and it is seed procured from these genetically hardy strains that are planted for ornament in colder parts of the world. An essential oil extracted from Eucalyptus leaves contains compounds that are powerful natural disinfectants and can be toxic in large quantities. Several marsupial herbivores , notably koalas and some possums , are relatively tolerant of it. The close correlation of these oils with other more potent toxins called formylated phloroglucinol compounds ( euglobals , macrocarpals and sideroxylonals ) allows koalas and other marsupial species to make food choices based on
3834-444: The juvenile and adult phases. In all except a few species, the leaves form in pairs on opposite sides of a square stem, consecutive pairs being at right angles to each other (decussate). In some narrow-leaved species, for example E. oleosa , the seedling leaves after the second leaf pair are often clustered in a detectable spiral arrangement about a five-sided stem. After the spiral phase, which may last from several to many nodes,
3905-471: The juvenile leaf form even when the plant is reproductively mature. Some species, such as E. macrocarpa , E. rhodantha , and E. crucis , are sought-after ornamentals due to this lifelong juvenile leaf form. A few species, such as E. petraea , E. dundasii , and E. lansdowneana , have shiny green leaves throughout their life cycle. Eucalyptus caesia exhibits the opposite pattern of leaf development to most Eucalyptus , with shiny green leaves in
3976-422: The mature seed pods of Corymbia torelliana , resulting in mellitochory as the seeds get stuck onto the corbiculae of the bees and sometimes are successfully disposed of by colony members that remove them. But usually, they get stuck in the hives or near hive entrances instead, hence also making it a minor nuisance for some keepers as they can take up a lot of space. Fortunately, this is only known to occur in
4047-555: The modern vegetation, the fossil record is very scarce throughout much of the Cenozoic , and suggests that this rise to dominance is a geologically more recent phenomenon. The oldest reliably dated macrofossil of Eucalyptus is a 21-million-year-old tree-stump encased in basalt in the upper Lachlan Valley in New South Wales . Other fossils have been found, but many are either unreliably dated or else unreliably identified. It
4118-486: The past as Heteropyxidaceae and Psiloxylaceae. However, Wilson et al. included them in Myrtaceae. These two genera are presently believed to be the earliest arising and surviving lineages of Myrtaceae. The most recent classification recognizes 17 tribes and two subfamilies, Myrtoideae and Psiloxyloideae, based on a phylogenetic analysis of plastid DNA. Many new species are being described annually from throughout
4189-456: The production of pulpwood . Eucalyptus are the basis for several industries, such as sawmilling, pulp, charcoal and others. Several species have become invasive and are causing major problems for local ecosystems, mainly due to the absence of wildlife corridors and rotations management. Eucalypts have many uses which have made them economically important trees, and they have become a cash crop in poor areas such as Timbuktu , Mali and
4260-461: The range of Myrtaceae. Likewise, new genera are being described nearly yearly. Following Wilson (2011) Subfamily Psiloxyloideae Subfamily Myrtoideae 127 genera are currently accepted: Myrtaceae is foraged by many stingless bees, especially by species such as Melipona bicolor which gather pollen from this plant family. Some Australian species such as Tetragonula hockingsi and T. carbonaria are also known to collect resin from
4331-399: The sections renantheroideae and renantherae and the ratio of the amount of leucoanthocyanins varies considerably in certain species. Eucalyptus is one of three similar genera that are commonly referred to as " eucalypts ", the others being Corymbia and Angophora . Many species, though by no means all, are known as gum trees because they exude copious kino from any break in
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#17327871713294402-433: The seedling stage and dull, glaucous leaves in mature crowns. The contrast between juvenile and adult leaf phases is valuable in field identification. Four leaf phases are recognised in the development of a Eucalyptus plant: the 'seedling', 'juvenile', 'intermediate', and 'adult' phases. However, no definite transitional point occurs between the phases. The intermediate phase, when the largest leaves are often formed, links
4473-957: The smell of the leaves. For koalas, these compounds are the most important factor in leaf choice. A wide variety of insects also feed exclusively on Eucalyptus leaves, such as beetles in the genus Paropsisterna . The eusocial beetle Austroplatypus incompertus makes and defends its galleries exclusively inside eucalypts, including some species of Eucalyptus and Corymbia . Fungal species Mycosphaerella and Teratosphaeria have been associated with leaf disease on various Eucalyptus species. Several fungal species from Teratosphaeriaceae family are causal agents in leaf diseases and stem cankers of Eucalyptus in Uruguay , and Australia . Eucalypts originated between 35 and 50 million years ago, not long after Australia-New Guinea separated from Gondwana , their rise coinciding with an increase in fossil charcoal deposits (suggesting that fire
4544-565: The subgenera Corymbia and Blakella . Species of Corymbia occur in all mainland states of Australia and in the Northern Territory. There are about 100 species, all endemic to Australia except for four species that also occur in New Guinea, and one that is endemic to that country. Eucalyptus Eucalyptus ( / ˌ juː k ə ˈ l ɪ p t ə s / ) is a genus of more than 700 species of flowering plants in
4615-420: The time of late Eocene differentiation. Recent estimates suggest the Myrtaceae include about 5,950 species in about 132 genera. The family has a wide distribution in tropical and warm-temperate regions of the world, and is common in many of the world's biodiversity hotspots . Genera with capsular fruits such as Eucalyptus , Corymbia , Angophora , Leptospermum , and Melaleuca are absent from
4686-517: The time. He coined the generic name from the Greek roots eu and calyptos , meaning "well" and "covered" in reference to the operculum of the flower bud which protects the developing flower parts as the flower develops and is shed by the pressure of the emerging stamens at flowering. The name obliqua was derived from the Latin obliquus , meaning "oblique", which is the botanical term describing
4757-400: The world. Other important Australian genera are Callistemon (bottlebrushes), Syzygium , and Melaleuca (paperbarks). Species of the genus Osbornia , native to Australasia, are mangroves . Eugenia , Myrcia , and Calyptranthes are among the larger genera in the neotropics. Historically, the Myrtaceae were divided into two subfamilies. Subfamily Myrtoideae (about 75 genera)
4828-656: Was a factor even then), but they remained a minor component of the Tertiary rainforest until about 20 million years ago, when the gradual drying of the continent and depletion of soil nutrients led to the development of a more open forest type, predominantly Casuarina and Acacia species. The two valuable timber trees, alpine ash E. delegatensis and Australian mountain ash E. regnans , are killed by fire and only regenerate from seed. The same 2003 bushfire that had little impact on forests around Canberra resulted in thousands of hectares of dead ash forests. However,
4899-475: Was first formally described in 1789 by Charles Louis L'Héritier de Brutelle who published the description in his book Sertum Anglicum, seu, Plantae rariores quae in hortis juxta Londinum along with a description of the type species , Eucalyptus obliqua . The name Eucalyptus is derived from the Ancient Greek words "eu" meaning 'well' and "calyptos" 'covered', referring to the operculum covering
4970-743: Was recognized as having dry, dehiscent fruits (capsules) and leaves arranged spirally or alternate. The Leptospermoideae are found mostly in Australasia, with a centre of diversity in Australia. Many genera in Western Australia have greatly reduced leaves and flowers typical of more xeric habitats. The division of the Myrtaceae into Leptospermoideae and Myrtoideae was challenged by a number of authors, including Johnson and Briggs (1984), who identified 14 tribes or clades within Myrtaceae, and found Myrtoideae to be polyphyletic. Molecular studies by several groups of authors, as of 2008, have confirmed
5041-513: Was recognized as having fleshy fruits and opposite, entire leaves. Most genera in this subfamily have one of three easily recognized types of embryos. The genera of Myrtoideae can be very difficult to distinguish in the absence of mature fruits. Myrtoideae are found worldwide in subtropical and tropical regions, with centers of diversity in the Neotropics, northeastern Australia, and Malesia. In contrast, subfamily Leptospermoideae (about 80 genera)
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