Eucalyptus cordata
{{Short description|Species of eucalyptus}}
{{Speciesbox
|name = Heart-leaved silver gum
|image = Eucalyptus cordata.jpg
|image_caption = Eucalyptus cordata, Melbourne
|genus = Eucalyptus
|species = cordata
| status = NT
| status_system = IUCN3.1
|authority = Labill.{{cite web|title=Eucalyptus cordata|url= https://biodiversity.org.au/nsl/services/apc-format/display/113772|publisher=Australian Plant Census|access-date=13 May 2019}}
|range_map = E. cordata.JPG
|range_map_caption = E. cordata, field distribution
}}
Eucalyptus cordata, commonly known as the heart-leaved silver gum{{cite web |title=Eucalyptus cordata |url=https://apps.lucidcentral.org/euclid/text/entities/eucalyptus_cordata_subsp._cordata.htm |publisher=Euclid: Centre for Australian National Biodiversity Research |access-date=4 June 2020}} is a shrub to medium-sized tree that is endemic to Tasmania. It has smooth bark throughout, mostly only juvenile, more or less heart-shaped, glaucous leaves, glaucous flower buds arranged in groups of three, white flowers and cylindrical or hemispherical fruit.Image:Eucalyptus cordata, juvenile leaves.jpgImage:E. cordata, buds.jpg
Description
Eucalyptus cordata is a scraggy shrub or tree that typically grows to a height of between {{cvt|3 and 25|m}} and forms a lignotuber. It has smooth greenish yellow to brown or grey bark throughout and has glaucous branchlets. Larger trees sometimes have rough bark on the lower part of the trunk. Its crown is mostly composed of juvenile leaves and adult leaves are usually only found at the top of the tallest trees. The leaves of young plants, coppice regrowth and mature plants have sessile leaves arranged in opposite pairs, the leaves egg-shaped to almost round, {{cvt|30-55|mm}} long and {{cvt|20-55|mm}} wide with wavy edges. Adult leaves, only present in the crown of tall trees, are arranged alternately, lance-shaped, {{cvt|75-130|mm}} long and {{cvt|20-38|mm}} wide on a flattened petiole {{cvt|15-20|mm}} long. The flower buds are arranged in groups of three in leaf axils on a peduncle {{cvt|2-9|mm}} long, the individual buds sessile or on a very short pedicel. Mature buds are oval to club-shaped, green or glaucous, {{cvt|9-13|mm}} long and {{cvt|7-9|mm}} wide with a rounded, flattened or beaked operculum. Flowering has been observed in most months, with peaks between May and June, September and November, and the flowers are white. The fruit is a woody cup-shaped, cylindrical or hemispherical capsule {{cvt|7-13|mm}} long and {{cvt|9-15|mm}} wide and sessile or on a very short pedicel.{{cite web |last1=Chippendale |first1=George M. |title=Eucalyptus cordata |url=https://profiles.ala.org.au/opus/foa/profile/Eucalyptus%20cordata |publisher=Australian Biological Resources Study, Department of the Environment and Energy, Canberra |access-date=13 May 2019}}{{cite journal |last1=Nicolle |first1=Dean |last2=Potts |first2=Brad M. |last3=McKinnon |first3=Gay E. |title=Eucalyptus cordata subsp. quadrangulosa (Myrtaceae), a new taxon of restricted distribution from southern Tasmania |journal=Papers and Proceedings of the Royal Society of Tasmania |date=2008 |volume=142 |issue=2 |pages=71–78 |doi=10.26749/rstpp.142.2.71 |url=https://eprints.utas.edu.au/8078/4/2.9_Nicolle_et_al.pdf |access-date=13 May 2019|doi-access=free }}
Taxonomy and naming
Eucalyptus cordata was first formally described in 1806 by Jacques Labillardière who published the description in Novae Hollandiae Plantarum Specimen.{{cite web|title=Eucalyptus cordata|url= https://id.biodiversity.org.au/instance/apni/456036|publisher=APNI|access-date=13 May 2019}}{{cite book |last1=Labillardière |first1=Jacques |title=Novae Hollandiae plantarum specimen (Volume 2) |date=1806 |location=Paris |page=13 |url=https://www.biodiversitylibrary.org/page/40882044#page/13/mode/1up |access-date=13 May 2019}} The specific epithet (cordata) is a Latin word meaning "heart-shaped"{{cite book|last1=Brown|first1=Roland Wilbur|author-link1=Roland W. Brown|title=The Composition of Scientific Words|date=1956|publisher=Smithsonian Institution Press|location=Washington, D.C.|page=402}} referring to the leaves.
In 2008, Dean Nicolle, Brad Potts and Gay McKinnon described two subspecies and the names have been accepted by the Australian Plant Census:
- Eucalyptus cordata Labill. subsp. cordata,{{cite web|title=Eucalyptus cordata subsp. cordata|url= https://biodiversity.org.au/nsl/services/apc-format/display/177514|publisher=Australian Plant Census|access-date=13 May 2019}} that has branchlets that are circular in cross section;
- Eucalyptus cordata subsp. quadrangulosa D.Nicolle, B.M.Potts & McKinnon,{{cite web|title=Eucalyptus cordata subsp. quadrangulosa|url= https://biodiversity.org.au/nsl/services/apc-format/display/216151|publisher=Australian Plant Census|access-date=13 May 2019}} that has branchlets that are square in cross-section.
Distribution and habitat
Heart-leaved silver gum has a restricted distribution in the south-east of Tasmania, growing at intermediate altitudes such as on the foothills of Mount Wellington, on the Snug Plains and around Port Arthur and Moogara. The tree makes an attractive ornamental with its large, glaucous juvenile leaves, which often persist in the crown.Brooker, I. & Kleinig, D., Eucalyptus, An illustrated guide to identification, Reed Books, Melbourne, 1996 Subspecies cordata mainly occurs south from Triabunna and is found on Bruny and Maria Islands. Subspecies quadrangulosa is centred on the Wellington Range but is most prolific on the Snug Plains.
References
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{{Authority control}}
Category:Myrtales of Australia
Category:Endemic flora of Tasmania