sign in sign up
<<
Home , Actinostrobus arenarius, Anigozanthos bicolor, Anigozanthos rufus, Beaufortia micrantha, Boronia molloyae, Byblis gigantea

Formations in the Southwest Australian BioProvince

Peter Martin Rhind

Southwest Australian Unlike most of the World’s hardwood forests this type of forest is almost exclusively dominated by a single the Jarrah ( marginata), which can form almost pure stands in certain areas especially where laterite soils predominate. The only other commonly associated are Eucalyptus calophylla (marri), E. patens (blacknut) and E. wandoo (wandoo). Commonly associated under storey species include the strange Casuarine fraserana and various () such as grandis, B. menziesii and B. attenuata. However, in addition there are various arborescent monocots such as the endemic Dasypogon hookeri, Kingia australis and Xanthorrhoea gracilis (Xanthorrhoeaceae). The most common liana is the endemic Kennedia coccinea () and, in fact, both lianas and creepers are common features of these forests. The layer, unlike the canopy, is also rich in species with many endemics. The most common of these is latifolia (Proteaceae), while other species include alata, barbigerus, glumaceum, Dryandra praemorsa, willsoni, lissocarpha, sphaerocephalus (Proteaceae), Andersonia axilliflora, Astroloma ciliatum (Epacridaceae), preissii (), Chorizema dicksonii, cordata, Gastrolobium villosum (Fabaceae), Darwinia carnea, (), Hemiandra linearis (Lamiaceae), Hibbertia hypericoides (Dilleniaceae), Lechenaultia biloba, Scaevola platyphylla (Goodenaceae), and Primelea rosea (Thymeleaceae). The ground layer is also richly endowed with endemics including various orchids such as gemmata, Caladenia macrostylis, Caladenia sericea, fimbria, barbata, Pterostylis recurva and Thelymitra crinita (), while other ground dwelling, largely perennial herbs include Anigozanthos bicolor, Conostylis androstemma, (Haemodoraceae), Dampiera linearis (Goodeniaceae), the insectivorous microphylla and D. platystigma (Droseraceae), the ground hugging Dryandra nivea (Proteaceae), Goodenia fasciculate, Scaevola striata (Goodeniaceae), Kennedia stirlingii (Fabaceae), Orthrosanthus laxus, xanthina (Iridaceae), Ptilotus manglesii (Amaranthaceae), Tetratheca viminea (Tremandraceae) and Trichocline spathulata (Asteraceae).

A slightly sinister aspect of these forests is the many toxic species. These are particularly prevalent in the endemic Gastrolobium such as Gastrolobium calycinum (york road poison). Other highly toxic species include the endemic Isotoma hypocrateriformis (woodbridge poison) of the Lobelliaceae, various species of Oxylobium and the endemic cycad Macrozamia riedlei (Zamiaceae). These forests also provide habitat for the strange parasitic plant Pilostyles hamiltonii - Australia’s only representative of the family Rafflesiaceae. A better-known example is Rafflesia arnoldii, which has the World’s largest flower. In contrast Pilostyles has comparatively small flowers, just a few millimeters across, but like its larger relatives, spends most of its life cycle in the tissues of various host , which locally include various members of the genus Daviesia.

Southwest Australian On the loams and sandy loams over granitic and gneissic rocks the forests are mainly dominated by the endemic (karri), which is credited with being one of the three tallest hardwoods in the World measuring up to 90 m. In fact, it dwarfs most of the associated , although one of these, , can reach heights of 70 m. Other trees include Agonis juniperina and Eucalypus guilfoylei, while smaller trees Copyright © 2010 Peter Martin Rhind growing far below the karri canopy include the endemic (Myrtaceae). Altogether there may be three or four stories to these forests. A dense shrub layer is always present and commonly includes Trymalium spathulatum and the endemic quercifolia (). Other endemic include Acacia pentodenia (Fabaceae), Chorilaena quercifolia (Rutaceae), Hibbertia cuneiformis (Dilleniaceae), verticillatus (Fabaceae), and a number of very attractive species such as Boronia gracilipes, angustifolia (Rutaceae), Chorizema ilicifolium and (Fabaceae). Few members of the southern heath family Epacridaceae occur in these forests, but the endemic may be found. Underneath the shrubs large quantities of litter, bark and leaves accumulate. Despite this a number of herbaceous plants occur including various endemic species such as Dampiera hederacea (Goodeniaceae), and at least five species of fern. Of these Pteridium esculentum (a native bracken) is the most common, and is the largest native species growing to heights of 2 m, while other include Adiantum aethiopicum and Lindsaea linearis.

Southwest Australian Coastal Limestone Communities In the more exposed situations where salt spray is driven inland by winter storms, just a few small shrubs of Frankenia pauciflora mainly colonize this coastal limestone. Further inland this gives way to a heathland community of Dryandra, Hakea and , while in the more sheltered valleys trees such as , Eucalyptus gomphocephala, Melaleuca lanceolata may occur. Endemic species found here include shrubs such as Diplolaena angustifolia (Rutaceae), Dryandra sessilis (Proteaceae), Melaleuca heugelii (Myrtaceae), and the creeper Kennedia coccinea (Fabaceae).

Southwest Australian Coastal Sand Dune Communities In the mobile dunes exposed to salt-laden winds, the main species include various dune grasses such as Spinifex longifolius and S. hirsutus, together with a variety of cosmopolitan species like Cakile maritima. In the more stable zones further inland a form of low heath occurs composed of species such as Acanthocarpus preissii, and the endemic Acacia pullchella (Fabaceae), Calectasia cyanea (Xanthorrhoeaceae) and Hibbertia hypericoides (Dilleniaceae). Other endemics associated with dunes include the shrubs Diplolaena dampieri (Rutaceae) and Rhagodia radiata (Chenopodiaceae). Banksias (Proteaceae) are also a feature of the coastal dunes in the south, particularly between Hopetoun and Israelite Bay. Here showy species such as , B. nutans and the endemic B. baxteri and B coccinea occur. Deeper coastal sand provides habitat for members of the endemic genera Anigozanthos and Conostylis including Anigozanthos rufus and the attractive Conostylis bealiana, C. petrophiloides and C. vaginata.

Southwest Australian Bush of Southern Sand Plains This region includes the undulating plains along the south coast from Pallinup River to Israelite Bay and extends inland to Lake Grace. Two of the more prominent shrubs of these southern bush lands are Hakea crassifolia and the endemic inervis (Proteaceae). The latter represents a near endemic genus with all but one species endemic to the southwest. Another widespread endemic shrub found here is the unusual fucifolia (Proteaceae), while other important shrubby species are the so-called bottlebrushes micrantha, B. orbifolia and B. schaueri, and the wax flowers axillare and C. megalopetalum (Mrytaceae). Both genera are endemic to the southwest, with some 15 species of Chamelaucium. Among the endemic herbs are species of the endemic genus Anthotium (Goodeniaceae) including Anthotium humile and A. rubiflorum. Both have perennial rootstocks and rosetted linear leaves.

Copyright © 2010 Peter Martin Rhind Southwest Australian Bush of Northern Sand Plains These sandy plains occur north of between Moore River and Shark Bay. Like their southern counterpart two of the most prominent families are Proteaceae and Myrtaceae. In the former there are at least 20 species of Banksia including the endemic B. burdettii and many species of the endemic Dryandra such as D. nana, D. carlinoides, D. kippistiana, D. shuttleworthiana and D. speciosa. Most dryandras and banksias produce abundant nectar and although birds and insects are attracted to this, it seems that small marsupials are the main pollinators. Other conspicuous members of the Proteaceae include the , such as the spectacular white plume grevellea () and the endemic smokebush . Of the Myrtaceae, the intriguing genus Darwinia, with its great diversity of inflorescences, is well represented with some 30 species endemic to the southwest. Two of the more common of these are Darwinia neildiana and D. speciosa. Other indigenous members of this family include various species of the genus Calothamnus. All 25 species of this genus are endemic to the southwest but only about 10 occur on the northern sand plains including Calothamnus blepharospermus, C. homalophyllus and C. quadrifidus. Also present are many poisonous plants of the endemic genus Gastrolobium, such as Gastrolobium oxylobioides, which have caused problems for pastoralists since the early days of settlement. Flowers of many colours are seen in the family Goodeniaceae and even in the genus Lechenaultia with about 25 species, flowers may be blue, white, yellow, red, orange or green. One of the more common of these is the endemic blue lechenaultia (Lechenaultia biloba). In areas of deep sand are various members of the enigmatic, endemic genus Anigozanthos, including and A. pulcherrimus (Haemodoraceae), while other endemic members of this family are the so-called cotton-heads such as , C. candicans and C. stylidioides. Other endemic genera that are well represented in this area are Beaufortia, Hypocalymma and Scholtzia. Apart from Xanthorrhoea preissii, moncots are not a dominant feature of these sand plains, but the allied Kingia australis is found in a few areas. Orchids are also rarely found but members of the genera Caladenia, Diuris and Thelymitra may be encountered including the endemic Caladenia crebar and C. flava (Orchidaceae). Finally several species of native grow in the area include the endemic sand plain cypress ( arenarius) and its smaller relative the endemic dwarf cypress (A. acuminatus).

Southwest Australian Swamps The most common shrub found in the heavier swamp soils is the swamp tea-tree ( ellipticum), while in areas subject to seasonal flooding there may various species of shrubby Banksia, such as the endemic (Proteaceae), and the endemic shrub Hypocalymma angustifolium (Myrtaceae). The slightly dryer areas provide home for various members of the Haemodoraceae including the endemic shrub Anigozanthos viridus, as well as some of the less spectacular species of the endemic genus Tribonanthes (Haemodoraceae). Also in these areas, especially ones subjected to winter wetness, endemics such as red swamp cranberry Astroloma stomarrhena (Epacridaceae) and Leptocarpus canus () occur. Some of the more ephemeral swamps, particularly those near the foothills of the Darling Range, are noted for their prevalence of endemic plants, and include a number of insectivorous species, such as gigantea (Byblidaceae), several sun dews like Drosera menziesii (Droseraceae) and members of the bladderwort family (Lentibulariaceae) such as Utricularia menziesii. Other endemic species found in the swamps of this BioProvince include the shrubs Acacia baxteri (Fabaceae), Beaufortia sparsa, Melaleuca polygaloides (Myrtaceae), Boronia heterophylla, Boronia molloyae (Rutaceae), Cosmelia rubra (Epacridaceae), the perennial herbs Adenanthus obovata (Proteaceae), Anigozanthos flavidus (Haemodoraceae), the pitcher plant Cephalotis folliculare (Cephalotaceae), and the orchids Drakaea elastica,

Copyright © 2010 Peter Martin Rhind Eriochilus scaber and Prasophyllum regium (Orchidaceae). The latter (P. regium) is one of the giants of the orchid world growing to heights of up to 2 m.

Further information required.

References

Aplin, T. E. H. 1975. The Vegetation of . In: Western Australian Year Book No. 14. W. M. Bartlett. Australian Bureau of Statistics.

Beadle, N. C. W. 1981. The Vegetation of Australia. Gustav Fischer Verlag.

Beard, J. S., Chapman, A. R. & Gioia, P. 2000. Species richness and endemism in the Western Australian Flora. Journal of Biogeography, 27: 1257-1268.

Erickson, R. et al. 1973. Flowers and Plants of Western Australia. A. H. & A. W. Reed.

Gardner, C. A. 1959. The vegetation of western Australia. In: Biogeography and Ecology in Australia. Monographiae Biologicae, 8: 275-281.

Sauer, J. 1964. Geographic reconnaissance of western Australian seashore vegetation. Australian Journal of , 13: 39-69.

Copyright © 2010 Peter Martin Rhind