Eucalyptus pauciflora

Eucalyptus pauciflora, commonly known as snow gum, cabbage gum or white sally,[2] is a species of tree or mallee that is native to eastern Australia. It has smooth bark, lance-shaped to elliptical leaves, flower buds in clusters of between seven and fifteen, white flowers and cup-shaped, conical or hemispherical fruit. It is widespread and locally common in woodland in cold sites above 700 m (2,300 ft) altitude.

Snow gum
Eucalyptus pauciflora near Thredbo
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Myrtales
Family: Myrtaceae
Genus: Eucalyptus
Species:
E. pauciflora
Binomial name
Eucalyptus pauciflora
Synonyms[1]
Bark
Flower buds and flowers

Description

Eucalyptus pauciflora is a tree or mallee, that typically grows to a height of 20–30 m (66–98 ft) and forms a lignotuber. It has smooth white, grey or yellow bark that is shed in ribbons and sometimes has insect scribbles. Young plants and coppice regrowth have dull, bluish green or glaucous, broadly lance-shaped to egg-shaped leaves that are 44–170 mm (1.7–6.7 in) long and 20–85 mm (0.79–3.35 in) wide. Adult leaves are the same shade of glossy green on both sides, lance-shaped to curved or elliptical, 60–200 mm (2.4–7.9 in) long and 12–50 mm (0.47–1.97 in) wide, tapering to a petiole 8–33 mm (0.31–1.30 in) long. The flower buds are arranged in leaf axils in cluster of between seven and fifteen, sometimes more, on an unbranched peduncle 3–15 mm (0.12–0.59 in) long, the individual buds on pedicels up to 6 mm (0.24 in) long. Mature buds are oval, 4–8 mm (0.16–0.31 in) long and 3–5 mm (0.12–0.20 in) wide with a conical to rounded operculum. Flowering occurs from October to February and the flowers are white. The fruit is a woody, cup-shaped, conical or hemispherical capsule 5–11 mm (0.20–0.43 in) long and wide.[2][3][4][5]

Taxonomy

Eucalyptus pauciflora was first formally described in 1827 by Kurt Polycarp Joachim Sprengel from an unpublished description by Franz Sieber. Sprengel published the description in Systema Vegetabilium.[6][7] The specific epithet pauciflora is from the Latin pauciflorus meaning "few-flowered".[8][9] The term pauciflora (few-flowered) is a misnomer, and may originate in an early collected specimen losing its buds in transit.[10]

Six subspecies are recognised by the Australian Plant Census as at 30 November 2019:

Distribution and habitat

Snow gum grows in woodland along the ranges and tablelands, in flat, cold sites above 700 m (2,300 ft) from the far south-east of Queensland, through New South Wales, the Australian Capital Territory, and Victoria, to near Mount Gambier in South Australia and Tasmania.[16]

In Tasmania the species hybridises with Eucalyptus coccifera and Eucalyptus amygdalina.[17]

Ecology

Snow gum is amongst the hardiest of all eucalyptus species, surviving the severe winter temperatures of the Australian Alps.[10] The species regenerates from seed, by epicormic shoots below the bark, and from lignotubers. It is the most cold-tolerant species of eucalyptus, with E. pauciflora subsp. niphophila surviving temperatures down to −23 °C (−9 °F) and year-round frosts. It has been introduced to Norway.[18]

Influence on snowpack processes

At altitudes where stands of snow gum coincide with seasonal snowfall above an altitude of about 1,500 m (4,900 ft), the trees have been shown to increase snowpack accumulation and moderate melt, making snow gum critically important to the hydrology and water resources of southeast Australia. Bushfire impact on snow gums alters these effects and leads to reduced snowpack longevity and greater evaporation/sublimation processes, in turn reducing snowpack runoff available for ecosystem and human use.[19] It is estimated that the 2019-2020 bushfires impacted 462 km2 (33%) of mapped snow gum forest that regularly has seasonal snowpack, which would equate to a reduction in annual snowpack runoff of 25.6 gigalitres (about 10,240 olympic swimming pools).

Use in horticulture

In cultivation in the UK, Eucalyptus pauciflora subsp. niphophila[20] and Eucalyptus pauciflora subsp. debeuzevillei[21] have gained the Royal Horticultural Society's Award of Garden Merit.

  • Image showing the tree's ability to survive in deep snow
  • Image showing how the branches bend rather than break with the weight of the snow and how this causes snow to be lost from the leaves
  • Snow gum woodland below the tree line

References
  1. "Eucalyptus pauciflora". Australian Plant Census. Retrieved 13 December 2019.
  2. "Eucalyptus pauciflora". Euclid: Centre for Australian National Biodiversity Research. Retrieved 30 May 2020.
  3. Chippendale, George M. "Eucalyptus pauciflora". Australian Biological Resources Study, Department of the Environment and Energy, Canberra. Retrieved 13 December 2019.
  4. Brooker, M. Ian H.; Slee, Andrew V. "Eucalyptus pauciflora". Royal Botanic Gardens Victoria. Retrieved 13 December 2019.
  5. Hill, Ken. "Eucalyptus pauciflora". Royal Botanic Garden Sydney. Retrieved 13 December 2019.
  6. "Eucalyptus pauciflora". APNI. Retrieved 13 December 2019.
  7. Sprengel, Kurt P.J. (1827). Curae Posteriores in Systema Vegetabilium (17 ed.). New York: Sumtibus Librariae Dieterichianae. p. 195. Retrieved 13 December 2019.
  8. Allen J. Coombes The A to Z of Plant Names: A Quick Reference Guide to 4000 Garden Plants, p. 106, at Google Books
  9. D. Gledhill The Names of Plants, p. 220, at Google Books
  10. "Eucalyptus pauciflora". Kew Royal Botanic Gardens. Archived from the original on 2013-03-12. Retrieved 26 July 2013.
  11. "Eucalyptus pauciflora subsp. acerina". Australian Plant Census. Retrieved 13 December 2019.
  12. "Eucalyptus pauciflora subsp. debeuzevillei". Australian Plant Census. Retrieved 13 December 2019.
  13. "Eucalyptus pauciflora subsp. hedraia". Australian Plant Census. Retrieved 13 December 2019.
  14. "Eucalyptus pauciflora subsp. niphophila". Australian Plant Census. Retrieved 13 December 2019.
  15. "Eucalyptus pauciflora subsp. parvifructa". Australian Plant Census. Retrieved 13 December 2019.
  16. "Eucalyptus pauciflora Sieber ex Spreng". Atlas of Living Australia.
  17. Kirkpatrick, J.B.; Backhouse, Sue (2004). Native trees of Tasmania (7th ed.). Sandy Bay, TAS: Pandani Press. pp. 92–93. ISBN 0-646-43088-2.
  18. "Snow gum in Norway". Archived from the original on 2009-06-18.
  19. Schwartz, Andrew J.; McGowan, Hamish; Callow, Nik (2020-11-15). "Impact of fire on montane snowpack energy balance in Snow Gum forest stands". Agricultural and Forest Meteorology. 294: 108164. doi:10.1016/j.agrformet.2020.108164. ISSN 0168-1923.
  20. "Eucalyptus pauciflora subsp. niphophila". RHS. Retrieved 19 June 2020.
  21. "Eucalyptus pauciflora subsp. debeuzevillei". RHS. Retrieved 19 June 2020.

Further reading
  • Iglesias Trabado, Gustavo (2007). Eucalyptus from Alpine Australia. Notes on taxonomy and cultivation in cold temperate climates, In: EUCALYPTOLOGICS
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