Eremaean (Central Australian) Mallee

Mallee is the analagous term for chaparral in Australia. It is an aboriginal word for eucalypts of shrub proportions with many stems arising from a large lignutuber.

Vegetation dominated by mallee tends to occur in scattered patches but these may be relicts of more extensive formations in the past. Precise seasonal incidence of rain appears to be a subsidiary factor as far as their distribution is concerned. Soils, on the other hand, play a more significant role with most mallee communities occurring on well-drained soils of coarse texture. Under story species also vary with soils types and can be broadly divided into calcicole, halophyte and xerophyte assemblages. The dominant mallee eucalypts in the Eremaean zone include Eucalyptus diversifolia, E. dumosa, E. foecunda, E. gracilis, E. incrassata, E. loxophlebia, E. oleosa, E. pyriformis, E. socialis and the endemic or near endemic E. concinna, E. eremophila, E. leptopoda and E. oldenfieldii (Myrtaceae). Mallee dominated by E. diversifolia is mainly confined to wetter areas in South Australia including the Eyre Peninsula and Kangaroo Island. Among the associated species are a number of endemic or near endemic eucalypts such as E. cneorifolia (mainly Kangaroo Island), E. remota (confined to Kangaroo Island) and E. lansdowniana (southern part of Eyre Peninsula). The under storey is largely composed of xerophytic species but composition varies. On Kangaroo Island, Hakea ulicina and Olearia teretifolia are the most abundant shrubs, but members of the Epacridaceae such as Acrotriche fasciculiflora, Astroloma conostephioides and Epacris impressa are also common. This assemblage is also unique in the presence of various species endemic to the island such as Adenanthos sericea (Proteaceae) and Petrophila multisecta (family?). Mallee dominated by Eucalyptus foecunda is mainly confined to the west where it can be found in association with Eucalyptus gracilis and E. oleasa on low dunes and around salt lakes. Shrubs of Meloleuca uncinata occasionally form a dense under storey, but in deep white sand adjacent to the coast Acacia cyclops becomes the principal under storey species. Other shrubs may include the endemic or near endemic Brachychiton gregorii (Sterculiaceae) and Eucalypus leptopoda (Myrtaceae). In the east, including the Nullarbar region, the main mallee type is dominated by E. dumosa, E. gracilis, E. oleosa and E. socialis, but may also include various other eucalypts such as the endemic or near endemic E. socialis (Myrtaceae).

The under storey can be divided into two main types. In the wetter areas the characteristic shrubs are Acacia oswaldii, Callitris preissii, Exocarpus aphyllus, Eucarya accuminata, Geijera linearifolia and Pittosporum phylliraeoides. In dryer areas species such as Eremophila scoparia, Heterodendron oleifolium, Myoporum platycarpum and the endemic Codonocarpus cotonifolius (Gyrostemonaceae) become more conspicuous components. A sporadic herbaceous layer is usually present chiefly composed of grasses such as Danthonia setacea and the endemic or near endemic Triodia scariosa (Poaceae). Also confined to Western Australia is mallee dominated by the endemic or near endemic Eucalyptus eremophila. Associated eucalypts may include E. anceps, E. calycogona, E. celastroides, E. erythronema, E. flactonia, E. fourestiana, E. leptocalyx, E. merrickae, E. ovularis or E. pileata.  Eucalyptus forestiana is the distinctive ‘fuchsia mallee’ with its four angled, orange-scarlet buds. Mallee dominated by Eucalyptus pyriformis and the two endemic or near endemic species E. leptopoda and E. oldenfieldii, sometimes referred to as sand plain mallee, stretches across the northern fringes of western areas virtually from the Indian Ocean to the arid central South Australia. Among the associated eucalypts are various endemic or near endemic species like Eucalyptus pimpiniana (Myrtaceae). However, this is a very loose association with many of the associated species having varying distributions. The under storey also comprises a varying assemblage of species such as Acacia longispinea, Anthrotroche myoporoides, Hakea buculenta, Micromyrtus peltigera, Verticordia ethleliana and the endemic or near endemic Plectrachne desertorum (Poaceae). Finally in the Kalgoorle area at the fringes of the arid zone mallee dominated by the endemic or near endemic Eucalyptus concinna can be found. It also extends into the Victoria Desert. Associated eucalypts include the endemic or near endemic Eucalyptus comitae-vallis, while at ground level there are scattered hummocks of Triodia scariosa and the annual herb Ptilotus exaltatus. Other eucalypts largely confined to the arid zone include Eucalyptus carnei, E. gamophylla, E. gillii, E. gongylocarpa, E. kingsmillii, E. lucasii, E. odontocarpa, E. pachyphylla and E. striaticalyx, but none of these form well defined alliances and their under storey species vary from place to place. Nevertheless, the ground layers often include members of the Australian endemic grass Triodia such as Triodia basedowii, T. concinna, T. longipes, T. pungens, and shrubs of the genus Eremophila (a genus largely confined to Eremaea) such as Eremophila leucophylla.

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