Description and Characteristics of Eucalyptus

  • Eucalyptus is a genus of flowering plants in the family Myrtaceae.
  • Most species of Eucalyptus are trees, often mallees, and a few are shrubs.
  • Eucalyptus plants have bark that is either smooth, fibrous, hard, or stringy.
  • The leaves of Eucalyptus have oil glands.
  • The fruit of Eucalyptus is a woody capsule commonly referred to as a gumnut.
  • Eucalypts vary in size and habit from shrubs to tall trees.
  • Mallees are multistemmed eucalypts that are rarely taller than 10 meters.
  • Mallets are eucalypts with a single thin trunk and a steeply branching habit.
  • Marlocks are shrubs or small trees with a single, short trunk and spreading, densely leafy branches.
  • Eucalyptus regnans is the tallest known flowering plant on Earth.
  • Eucalyptus trees have different types of bark, including stringybark, ironbark, tessellated bark, box bark, and ribbon bark.
  • Mature Eucalyptus leaves are commonly lanceolate, petiolate, and waxy or glossy green.
  • Seedling leaves are often opposite, sessile, and glaucous.
  • Some Eucalyptus species retain the juvenile leaf form even when mature.
  • Some species have shiny green leaves throughout their life cycle.
  • Leaf development in Eucalyptus plants goes through four phases: seedling, juvenile, intermediate, and adult.
  • Eucalyptus flowers have numerous fluffy stamens in various colors.
  • The stamens are enclosed in a cap known as an operculum.
  • As the stamens expand, the operculum is forced off, revealing the cup-like base of the flower.
  • Eucalyptus fruits are woody capsules or gumnuts.
  • Eucalyptus species have distinctive flowers and fruits that help identify them.

History and Distribution of Eucalyptus

  • Eucalypts were first seen by early European explorers and collectors in 1770.
  • Joseph Banks and Daniel Solander collected specimens of E. gummifera and E. platyphylla in Botany Bay.
  • In 1777, David Nelson collected a eucalypt on Bruny Island in Tasmania, which was named Eucalyptus obliqua.
  • James Edward Smith named several more species of Eucalyptus in the late 18th century.
  • Ferdinand von Mueller's work in the 19th century contributed greatly to the understanding of eucalypts.
  • Over 700 species of Eucalyptus are known.
  • Some species have diverged genetically and can be recognized by specific characteristics.
  • Many species appear to grade into one another, and intermediate forms are common.
  • Hybrid individuals have sometimes been named as new species.
  • Chemical compounds present in the leaves allow for discrimination between certain species.
  • Eucalyptus is one of three similar genera commonly referred to as eucalypts.
  • Many species are known as gum trees because they exude kino from breaks in the bark.
  • The generic name is derived from Greek words meaning 'well' and 'to cover,' in reference to the operculum on the calyx.
  • The other two related genera are Corymbia and Angophora.
  • Most Eucalyptus species are native to Australia.
  • A small number of species are found in adjacent areas of New Guinea and Indonesia.
  • Eucalyptus deglupta ranges as far north as the Philippines.
  • Eucalypts are cultivated in many parts of the world, including the Americas, Europe, Africa, and the Middle East.
  • Australia is covered by 92 million hectares of eucalypt forest, comprising three-quarters of the area covered by native forest.
  • The oldest definitive Eucalyptus fossils are from Patagonia in South America, dating back to the early Eocene.
  • Fossil leaves also occur in the Miocene of New Zealand.
  • The fossil record of Eucalyptus in Australia is scarce, suggesting its rise to dominance is a more recent phenomenon.
  • The oldest reliably dated macrofossil of Eucalyptus is a 21-million-year-old tree-stump found in New South Wales.
  • Extensive research has failed to uncover any Eucalyptus specimens in the Paleocene to Oligocene of South-Eastern Australia.

Tall Timber and Frost Intolerance

  • Eucalyptus regnans is the tallest flowering plant, reaching a height of 100.5m (330ft).
  • Coast Douglas-fir is similar in height, while coast redwood is taller.
  • Six other eucalypt species exceed 80 meters in height.
  • Most eucalypts are not tolerant of severe cold.
  • They are usually damaged by temperatures below -5°C (23°F).
  • Snow gums, such as Eucalyptus pauciflora, can withstand cold and frost down to about -20°C (-4°F).
  • Subspecies E. pauciflora subsp. niphophila and E. pauciflora subsp. debeuzevillei are even hardier.
  • Other species from central Tasmania, such as Eucalyptus coccifera, Eucalyptus subcrenulata, and Eucalyptus gunnii, have also produced cold-hardy forms.

Animal Relationships and Diseases on Plants

  • Eucalyptus leaves contain powerful natural disinfectants and can be toxic in large quantities.
  • Koalas and some possums are relatively tolerant of these compounds.
  • Koalas use the smell of the leaves to make food choices.
  • Eucalyptus flowers provide food for many

Eucalyptus - Wikipedia Data Sources

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