Eucalyptus citriodora Hook.
Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.
- Folk Medicine
- Yields and Economics
- Biotic Factors
Leaves yield a lemon-scented oil rich in citronellal, and favored in perfumery.
The wood is good for saw-timber, used for general construction, poles, railroad
ties, and tool handles. Bark may contain up to 12% tannin. Kenyans favor the
honey produced by this species.
Reported to be antiseptic and fumigant. Cubans place the leaves under the
sheets of fever patients, and inhale the steam from boiled leaves for cold and
various pulmonary problems. Cubans also poultice the leaves onto ulcers,
wounds, and other skin ailments. Guatemalans decoct the leafy shoots for
coughs (Morton, 1981). Orally administered leaf extracts in rabbits
artifically diabetic, produced temporary hypoglycemia and reduced the blood
sugar levels (Watt and Breyer-Brandwijk, 1962). Myrtillin, in the leaf
extract, is said to induce a temporary hypoglycemia (Atal and Kapur, 1981).
Dayal reported betulinic and ursolic acids, eucalyptin and b-sitosterol in
the leaves. Glabrous leaves may contain oil with 65.5% citronellal, 12.2%
citronellol, and 3.6% isopulegol; hairy leaves contain more oil with 86.690.1%
citronellal, 4.66.0% citronellol, and 0.70.8% isopulegol, 1-pinene,
b-pinene, and isovaleric aldehyde are also recovered (Morton, 1981). Bark
contains ca 9% tannin (Watt and Breyer-Brandwijk, 1962). The young leaf is
reported to contain citric-, glutaric-, malic-, quinic-, shikimic-
(carcinogenic), and succinic-acids (Watt and Breyer Brandwijk, 1962). Leaves
and fruits test positive for flavonoids and sterols.
Citronellal found in Eucalyptus and Melissa is reported to be mutagenic (Lewis
and Elvin-Lewis, 1977).
Evergreen tree 2440 m high with tall straight trunk 0.61.3 m in diameter, and
thin, graceful crown of drooping foliage. Bark smooth, gray, peeling off in
thin irregular scales or patches and becoming mottled, exposing whitish or
faintly bluish inner layer with powdery surfaces appearing dimpled. Twigs
slender, slightly flattened, light green, tinged with brown. Leaves alternate,
narrowly lance-shaped, 1020 cm long, 12.5 cm wide, apically acuminate,
basally acute, entire, glabrous, thin, light green on both surfaces, with many
fine parallel straight veins and with vein inside edge. Corymbs terminal and
at leaf ba"s, to 6 cm long, branched. Flowers many, 35 on equal short stalks
(umbels) from ovoid buds 812 mm long, 58 mm wide. Stamens many, threadlikes,
white, 6 mm long, spreading ca 12 mm across, anthers with long gland. Pistil
inferior 3-celled ovary and long, stout style. Capsules few, urn-shaped or
ovoid, narrowed into short neck, 1012 mm long, 810 mm wide, brown with
scattered raised dots. Seeds few, irregularly ellipsoid, 45 mm long, shiny
black (Little, 1983).
Reported from the Australian Center of Diversity, lemon-scented gum, or cvs
thereof, is reported to tolerate clay, drought, gravel, laterites, light
frosts, podzols, poor soil, and slopes, but is not very tolerant of
waterlogging. The hybrid with E. torelliana is showing promise in
Nigeria (NAS, 1980a). Gupta et al. (1981) obtained multiple shoots from
20-year old terminal bulbs in culture. Shoots were also obtained from seedling
explants. They estimate they can produce 100,000 plants from one mature tree
bud in one year.(2n = 20, 22, 28)
Said to occur naturally only on the central and northern coasts of Queensland,
Australia, but to fare well in much of Africa, Brazil, California, Hawaii,
India, even Portugal.
Said to grow where the rainfall, mostly summer, is 6 to 13 dm, with 57 month
dry season, withstanding high temperatures (2935°C mean monthly maximum)
and light frosts. In tropical and subtropical arid to semiarid zones, in
infertile clays, laterites, poor and gravelly soils and podzols, preferrably
In Zimbabwe, seeds are broadcast successfully on the ashes of recently burned
tracts. More usually seedlings are transplanted from the nursery. Seed
require no special treatment.. Though needing protection from frost and weeds
when young, older saplings show more tolerance to both. According to Irvine
(1961), seedlings transplant badly.
For oil extraction, trees are not allowed to mature to the timber stage.
Instead, they are lopped for the foliage; sucker shoots produce copious foliage.
Tanzania plantations, harvested on an 8-year coppice, produced an annual 15
m3/ha. Back in 1925, the essential oil from this species commanded
twice the price of that of E. globulus (MacMillan, 1946).
Firewood yields run 1021 m3/ha/yr (Fenton et al., 1977). The hard
heavy wood (sp. grav. 0.751.1) burns steadily and makes a good charcoal with
an ash content of 12%. This is the chief charcoal species of the Brazililan
Browne (1968) lists the following as affecting this species: (Bacteria)
Agrobacterium tumefaciens. (Fungi) Armillaria mellea, Fusarium
spp., Ganoderma colossum, G. lucidum, Phytophthora parasitica, Polyporus
rubidus, Puccinia psidii, Sclerotinia fuckeliana, Trametes cubensis,
Verticillium albo-atrum. (Coleoptera) Anomala cupripes, Dicasticus
affinis, Elytrurus griseus, Entypotrachelus meyeri, Systates surdus, Xyleborus
truncatus. (Hemiptera) Atelocera stictica, Eucalyptolyma maideni.
(Isoptera) Ancistrotermes amphidon, Coptotermes truncatus, Microtermes
spp., Pseudacanthotermes militaris. (Lepidoptera) Carea angulata,
Colocleora divisaria, Neocleora nigrisparsalis, Nudaurelia krucki,
Strepsicrates holotephras, Sylepta balteata, Thalassodes sp., Uzucha borealis.
(Orthoptera) Schistocerca gregaria.
Complete list of references for Duke, Handbook of Energy Crops
- Atal, C.K. and Kapur, B.M. 1982. (eds.) Cultivation and utilization of
medicinal plants. Regional Research Laboratory. Jammu - Tawi, India. 877 p.
- Browne, F.G. 1968. Pests and diseases of forest plantations trees. Clarendon
- Fenton, R., Roper, R.E., and Watt, G.R. 1977. Lowland tropical hardwoods.
External Aid Division, Ministry of Foreign Affairs. Wellington, N.Z.
- Gupta, P.K., Mascarenhas, A.F., and Jagannathan, V. 1981. Tissue culture of
forest treesclonal propagation of mature trees of Eucalyptus
citridora Horsk. by tissue culture. Plant Science Letters 20(3):195201.
- Irvine, F.R. 1961. Woody plants of Ghana. Oxford University Press, London.
- Lewis, W.H. and Elvin-Lewis, M.P.F. 1977. Medical botany. John Wiley &
Sons, New York.
- Little, E.L. Jr. 1983. Common fuelwood crops: a handbook for their
identification. McClain Printing Co., Parsons, WV.
- MacMillan, H.F. 1946. Tropical gardening and planting. MacMillan & Co.,
- Morton, J.F. 1981. Atlas of medicinal plants of middle America. Bahamas to
Yucatan. C.C. Thomas, Springfield, IL.
- N.A.S. 1980a. Firewood crops. Shrub and tree species for energy production.
National Academy of Sciences, Washington, DC.
- Watt, J.M. and Breyer-Brandwijk, M.G. 1962. The medicinal and poisonous plants
of southern and eastern Africa. 2nd ed. E.&S. Livingstone, Ltd., Edinburgh
Last update Tuesday, January 6, 1998 by aw