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The Major Groups of EucalyptsThe Genera Eucalyptus, Corymbia and AngophoraPrepared by Andrew Lyne
The Genus Eucalyptus L'Her.
There are some 700 species of Eucalyptus. Some 250 species occur in New South Wales (NSW) whilst 24 occur in the Australian Capital Territory (ACT). The following classification where subgenera are recognised is informal and comes from Hill (1991). Subgenus 1 - Eudesmiac. 20 species: 1 species in NSW, none in the ACT.Inflorescence simple, axillary. Sepals free at tips but fused to petaline operculum. Most species with stamens in 4 or 5 bundles. Filaments regularly inflexed in bud. Anthers versatile, oblong, dehiscing through parallel slits. Subgenus 2 - Nothocalyptus1 species: none in NSW or the ACT.Adult leaves strongly discolorous with open, looped venation. Inflorescences compound, terminal or axillary. Sepals free, scarious, shed early in bud development. Petals free or partly fused, displaying suture lines along junctions. Filaments regularly inflexed in bud. Outer stamens often partly infertile and in 4 bundles. Subgenus 3 - Symphyomyrtusc. 450 species: c. 140 species in NSW, 16 species in the ACT.A large and variable group. Inflorescence simple (except E. michaeliana, axillary, sometimes modified by aggregation. Sepaline and petaline opercula present, sepals (outer operculum) either shedding before anthesis or (very rarely) becoming fused with petaline operculum. Ovules in 4 or more rows on placenta, hemitropous. Seeds with a single integument.
Section 1 - Transversariac. 25 species: 14 species in NSW, none in the ACT.Leaves strongly discolorous. Venation regularly finely penniveined. Anthers oblong, dehiscing through parallel slits. Blue gums, grey gums and red mahoganies Section 2 - Bisectariac. 250 species: 8 species in NSW, none in the ACT.Inflorescences mostly simple, axillary. Cotyledons bisected. A large and diverse group of mainly WA mallees. Anther morphology is widely diverse. Section 3 - Dumariac. 65 species: 2 species in NSW, none in the ACT.Inflorescences simple, axillary. Filaments regularly inflexed in bud. Anthers cuneate, dehiscing through parallel slits. Mainly WA mallees. Section 4 - Exsertariac. 45 species: 19 species in NSW, 2 species in the ACT.Leaf venation open, with open reticulation and several oil glands per island. Inflorescences simple, axillary (except Eucalyptus michaeliana). Anthers oblong, dehiscing through parallel slits. (E. michaeliana and E. pumila differ in many respects from the remainder of the group, but in other details are placed nearest this group.)
Subgenus 4 - Monocalyptusc. 140 species c. 90 species in NSW, 11 species in the ACT.Inflorescences simple, axillary (paired in Eucalyptus fastigata and E. regnans). Sepals suppressed, the single petaline operculum persisting to anthesis. Anthers reniform, dehiscing through confluent slits (in all NSW species). Seed testa 2-layered. Ovules anatropous, in 2 rows on placenta.
Group 1 - White mahoganiesc. 10 species: 5 species in NSW, none in the ACT.Bark fully persistent, finely fibrous or stringy. Juvenile leaves glabrous. Group 2 - Stringybarksc. 40 species: 31 in NSW, 1 species in the ACT.Bark stringy (except in Eucalyptus deuaensis and E. olsenii). Juvenile leaves hairy with stellate hairs.
The Genus Corymbia K.D.Hill & L.A.S.Johnson
There are 113 species of Corymbia in Australia. 10 species occur in New South Wales (NSW) whilst one (at Jervis Bay only) occurs in the Australian Capital Territory (ACT). Generally, Corymbia can be recognised through a combination of characters. Bark parting in small polygonal scales, smooth or persistent. Inflorescence compound, terminal, comprising regular umbellasters. Filaments regularly inflexed in bud. Anthers versatile, oblong, dehiscing through parallel slits. There are seven recognised sections within Corymbia. The following is from Hill and Johnson (1995). Section 1 - FundoriaRed Bloodwoods.1 species: none in NSW or the ACT. Seeds dorsiventrally compressed, petals free, juvenile leaves subsessile, non-peltate. Section 2 - ApteriaRed Bloodwoods. 1 species: 1 species with 2 or 3 subspecies in NSW, none in the ACT. Seeds dorsiventrally compressed, petals free, juvenile leaves long-petiolate, peltate. Section 3 - RufariaRed Bloodwoods. A section comprising 14 series. 67 species: 4 species in NSW, none in the ACT. Seeds laterally compressed. Section 4 - OchrariaYellow Bloodwoods. 12 species: 1 species in NSW, none in the ACT. Seeds dorsiventrally compressed, petals fused into an operculum, sepaline operculum shedding well before anthesis, stigma smooth, fruits woody, juvenile leaves petiolate, inner operculum thickened. Section 5 - CadagariaCadagai. 1 species: none in NSW or the ACT. Seeds dorsiventrally compressed, petals fused into an operculum, sepaline operculum shedding well before anthesis, stigma smooth, fruits woody, juvenile leaves petiolate, inner operculum not thickened. Section 6 - PolitariaSpotted Gums. 4 species: 3 species in NSW, none in the ACT. Seeds dorsiventrally compressed, petals fused into an operculum, sepaline operculum shedding shortly before anthesis, stigma with short papillae. Section 7 - BlakeariaGhost Gums. A section comprising 9 series. 27 species: 1 species in NSW, none in the ACT. Seeds dorsiventrally compressed, petals fused into an operculum, sepaline operculum shedding well before anthesis, stigma smooth, fruits papery, juvenile leaves sessile.
The Genus Angophora Cav.
There are 7 species of Angophora in Australia. All species occur in New South Wales (NSW). None occur in the Australian Capital Territory (ACT).
( The information presented here comes from the references below. Descriptions of all Eucalyptus and Angophora species as recognized by Chippendale have been put online by the Environmental Resources Information Network (ERIN). Remember however, that Corymbia species were considered to belong to Eucalyptus ).
ReferencesBrooker, M.I.H. and Kleinig, D.A. (1990). Field Guide to Eucalypts. Vol. 1, Revised edition. Inkata Press Proprietary Limited, Melbourne and Sydney.Brooker, M.I.H. and Kleinig, D.A. (1990). Field Guide to Eucalypts. Vol. 2. Inkata Press Proprietary Limited, Melbourne and Sydney. Brooker, M.I.H. and Kleinig, D.A. (1994). Field Guide to Eucalypts. Vol. 3. Reed International Books Australia Pty Limited trading as Inkata Press. Chippendale, G.M. (1988). Angophora. In: Chippendale, G.M. Flora of Australia Vol. 19, Myrtaceae, Eucalyptus, Angophora, Australian Government Publising Service, Canberra. Chippendale, G.M. (1988). Eucalyptus. In: Chippendale, G.M. Flora of Australia Vol. 19, Myrtaceae, Eucalyptus, Angophora, Australian Government Publising Service, Canberra. Hill, K.D. (1991). Eucalyptus. In: Harden, G. Flora of New South Wales, Vol. 2. NSW University Press. Hill, K.D. and Johnson, L.A.S. (1995). Systematic studies in the eucalypts. 7. A revision of the bloodwoods, genus Corymbia (Myrtaceae). Telopea 6(2-3): 185-504.
An Introduction to the Eucalypts Updated by Andrew Lyne  |