Flora of the Houtman Abrolhos explained

This is a list of the terrestrial flora of the Houtman Abrolhos. Only vascular plants are listed — there have been some collections of mosses, liverworts and lichens from the Houtman Abrolhos, but no information has been published on these non-vascular groups.^[1]

The distribution of each species within each island group is provided. A list of islands is provided for species that occur on fewer than ten islands in a group; for species that occur on ten or more islands in a group, an island count is provided. Islands without a formally gazetted name are referred to by informal names, given in quotation marks.

A grey background indicates a naturalised species.

Scientific name	Common name	Distribution			Remarks	Image
		Wallabi Group (45 islands)	Easter Group (34 islands)	Pelsaert Group (41 islands)
Aizoaceae
Carpobrotus sp.
Carpobrotus virescens	Coastal Pigface	13 islands	25 islands	23 islands
Disphyma crassifolium subsp. clavellatum	Round-leaved Pigface
Mesembryanthemum crystallinum	Iceplant	40 islands	18 islands	30 islands	Naturalised
Sesuvium portulacastrum
Tetragonia decumbens	Sea Spinach				Naturalised
Amaranthaceae
Ptilotus divaricatus	Climbing Mulla Mulla
Ptilotus eriotrichus
Ptilotus gaudichaudii
Ptilotus obovatus	Cotton Bush
Ptilotus villosiflorus
Anthericaceae
Thysanotus patersonii
Apiaceae
Apium annuum
Apium prostratum	Sea Celery
Daucus glochidiatus	Australian Carrot
Hydrocotyle diantha				Basile I., Middle I.
Petroselinum crispum	Parsley				Naturalised
Trachymene pilosa	Native Parsnip
Apocynaceae
Alyxia buxifolia	Dysentery Bush
Asclepiadaceae
Sarcostemma viminale subsp. australe
Asphodelaceae
Bulbine semibarbata	Leek Lily
Asteraceae
Actinobole condensatum
Actites megalocarpa	Dune Thistle
Angianthus tomentosus	Camel-grass
Brachyscome ciliaris
Brachyscome iberidifolia
Calocephalus aervoides	Woolly Beauty-heads	East Wallabi I., West Wallabi I.			Rated "Priority Three - Poorly Known Taxa" in the Department of Environment and Conservation's Declared Rare and Priority Flora List.
Chthonocephalus tomentellus					Rated "Priority Two - Poorly Known Taxa" in the Department of Environment and Conservation's Declared Rare and Priority Flora List.
Conyza bonariensis	Flaxleaf Fleabane				Naturalised
Conyza sumatrensis	Tall Fleabane				Naturalised. Harvey et al. (2001) lists C. albida, but this is now a taxonomic synonym of C. sumatrensis.^[2]
Erigeron karvinskianus					Naturalised
Euchiton sphaericus
Gnaphalium indutum	Tiny Cudweed
Helichrysum luteoalbum	Jersey Cudweed				Naturalised. Harvey et al. (2001) lists Pseudognaphalium luteoalbum, but this is now a nomenclatural synonym of Helichrysum luteoalbum.^[3]
Hypochaeris glabra	Smooth Catsear				Naturalised
Lactuca saligna	Wild Lettuce				Naturalised
Olearia axillaris	Coastal Daisybush
Podotheca angustifolia	Sticky Longheads
Reichardia tingitana	False Sowthistle				Naturalised
Senecio glossanthus	Slender Groundsel
Senecio pinnatifolius		23 islands	17 islands	16 islands	Harvey et al. (2001) lists S. lautus but this name has been misapplied in Western Australia to S. pinnatifolius.^[4]
Sonchus oleraceus	Common Sowthistle	20 islands	19 islands	16 islands	Naturalised. Harvey et al. (2001) lists both S. oleraceus and S. tenerrimus on four islands, and S. tenerrimus alone on another. However, the latter name is now considered a misapplication against the former in Western Australia,^[5] so here the entries for these names have been pooled.
Urospermum picroides	False Hawkbit	10 islands	10 islands		Naturalised
Ursinia anthemoides	Ursinia				Naturalised.
Vittadinia cuneata var. cuneata	Woolly Vittadinia
Vittadinia sp.
Avicenniaceae
Avicennia marina	White Mangrove			14 islands
Boraginaceae
Cynoglossum australe	Australian Hound's-tongue				Harvey et al. (2001) lists this species, but according to FloraBase it does not occur in Western Australia.^[6]
Echium plantagineum	Paterson's Curse				Naturalised; classed as a noxious weed.^[7]
Trichodesma zeylanicum	Camel Bush
Brassicaceae
Brassica rapa					Naturalised
Cakile maritima	Sea Rocket	10 islands	13 islands	12 islands	Naturalised
Hornungia procumbens	Oval Purse	14 islands			Naturalised. Harvey et al. (2001) lists Hornungia procumbens on 13 islands, and Hymenolobus procumbens on another, but the latter name is now considered a synonym of the former.^[8]
Lepidium lyratogynum
Lepidium pseudoruderale
Lepidium puberulum		Eastern I., "First Sister Islet"	10 islands		Rated "Priority Four — Rare Taxa" in the Department of Environment and Conservation's system of Declared Rare and Priority Flora List.
Raphanus raphanistrum	Wild radish				Naturalised
Raphanus sativus	Radish				Naturalised
Sisymbrium irio	London Rocket				Naturalised
Sisymbrium orientale	Indian Hedge Mustard				Naturalised
Cactaceae
Opuntia stricta	Common Prickly Pear				Naturalised
Campanulaceae
Wahlenbergia gracilis
Wahlenbergia multicaulis
Capparaceae
Capparis spinosa	Coastal Caper
Caryophyllaceae
Cerastium glomeratum	Mouse Ear Chickweed				Naturalised
Petrorhagia dubia	Velvet Pink				Naturalised. Harvey et al. (2001) lists P. velutina, but this is now a taxonomic synonym of P. dubia.^[9]
Polycarpon tetraphyllum	Fourleaf Allseed				Naturalised
Sagina apetala	Annual Pearlwort				Naturalised
Silene gallica	French Catchfly				Naturalised
Silene nocturna	Mediterranean Catchfly				Naturalised
Spergularia diandra	Lesser Sand Spurry				Naturalised
Spergularia rubra	Sand Spurry	12 islands			Naturalised
Spergularia sp. 5 Leeman					Harvey et al. (2001) lists S. nesophila, but this is an unpublished manuscript name, which is considered a nomenclatural synonym of the above.^[10]
Stellaria media	Chickweed				Naturalised
Celastraceae
Stackhousia sp.					Harvey et al. (2001) lists this under Stackhousiaceae, but it is now generally treated under Celastraceae.^[11]
Stackhousia sp.					Harvey et al. (2001) lists this as Stackhousia viminea, but this name has been misapplied in Western Australia against three species: S. clementii, S. muricata and S. intermedia.^[12] Harvey et al. (2001) treats Stackhousia under Stackhousiaceae, but it is now generally treated under Celastraceae.
Tripterococcus brunonis					Harvey et al. (2001) lists this under Stackhousiaceae, but it is now generally treated under Celastraceae.
Chenopodiaceae
Atriplex amnicola	Swamp Saltbush
Atriplex bunburyana	Silver Saltbush
Atriplex cinerea	Grey Saltbush	27 islands	21 islands	22 islands
Atriplex paludosa	Marsh Saltbush
Atriplex paludosa subsp. baudinii
Atriplex vesicaria subsp. variabilis	Bladder Saltbush
Atriplex sp.	Saltbush	17 islands	10 islands	18 islands
Chenopodium album	Fat Hen				Naturalised
Chenopodium melanocarpum	Black Crumbweed
Chenopodium murale	Nettle-leaf Goosefoot				Naturalised
Chenopodium nitrariaceum	Nitre Goosefoot
Dysphania plantaginella
Enchylaena tomentosa	Barrier Saltbush	26 islands	11 islands	17 islands
Rhagodia baccata	Berry Saltbush
Rhagodia latifolia
Rhagodia preissii subsp. obovata
Rhagodia sp.
Salsola kali	Prickly Saltwort				Naturalised
Sarcocornia quinqueflora	Beaded Samphire	17 islands	19 islands	15 islands
Suaeda australis	Seablite	11 islands
Tecticornia arbuscula					Harvey et al. (2001) listed Sclerostegia arbuscula, but all Sclerostegia were transferred into Tecticornia in 2007.^[13]
Tecticornia halocnemoides	Shrubby Samphire		13 islands	25 islands	Harvey et al. (2001) listed Halosarcia halocnemoides, but all Halosarcia were transferred into Tecticornia in 2007.
Tecticornia lepidosperma subsp. bidens					Harvey et al. (2001) listed Halosarcia indica subsp. bidens, but all Halosarcia were transferred into Tecticornia in 2007.
Tecticornia sp.	Samphire				Harvey et al. (2001) listed Halosarcia sp., but all Halosarcia were transferred to Tecticornia in 2007.
Threlkeldia diffusa	Coast Bonefruit	33 islands	19 islands	20 islands
Colchicaceae
Wurmbea monantha
Convolvulaceae
Ipomoea cairica					Naturalised
Crassulaceae
Bryophyllum delagoense	Mother of Millions				Naturalised. In 2000 this poisonous weed was found to have colonised over half of Rat and Pigeon Islands.^[14]
Crassula colorata	Dense Stonecrop		10 islands
Crassula exserta
Cotyledon orbiculata
Cucurbitaceae
Cucurbita pepo
Cunoniaceae
Aphanopetalum clematideum
Cyperaceae
Ficinia nodosa	Knotted Club Rush				Harvey et al. (2001) listed Isolepis nodosa, but this species has since been transferred into Ficinia.^[15]
Isolepis marginata	Coarse Clubrush				Naturalised
Dasypogonaceae
Acanthocarpus preissii
Dilleniaceae
Hibbertia racemosa	Stalked Guinea Flower
Epacridaceae
Leucopogon insularis
Euphorbiaceae
Beyeria viscosa	Pinkwood
Euphorbia boophthona	Gascoyne Spurge
Euphorbia drummondii	Caustic Weed
Euphorbia tannensis
Euphorbia terracina	Geraldton Carnation Weed				Naturalised
Phyllanthus calycinus	False Boronia
Frankeniaceae
Frankenia pauciflora	Seaheath	11 islands
Gentianaceae
Centaurium erythraea	Common Centaury				Naturalised
Schenkia australis					Naturalised. Harvey et al. (2001) lists this as Centaurium spicatum, but this species has been transferred into Schenkia, and the Australian specimens segregated into a new species as S. australis. Harvey et al. (2001) also lists C. maritimum on East Wallabi Island, but this name has been misapplied for C. spicatum in Australia.^[16]
Geraniaceae
Erodium cicutarium	Common Storksbill				Naturalised
Erodium cygnorum	Blue Heronsbill
Pelargonium littorale
Pelargonium zonale					Naturalised. Harvey et al. (2001) lists this species, but FloraBase has no record of it occurring in Western Australia.^[17]
Goodeniaceae
Scaevola crassifolia	Thick-leaved Fan-flower
Haloragaceae
Haloragis trigonocarpa
Juncaceae
Juncus bufonius	Toad Rush				Naturalised
Juncaginaceae
Triglochin centrocarpa
Triglochin mucronata
Triglochin muelleri
Triglochin trichophora
Lamiaceae
Westringia dampieri
Liliaceae
Aloe sp.					Naturalised
Loganiaceae
Phyllangium paradoxum
Malvaceae
Lavatera sp.			"Shearwater Islet"
Malva preissiana	Australian Hollyhock	21 islands	15 islands	12 islands	Harvey et al. (2001) lists this as Lavatera plebeia, but this is now a synonym of M. preissiana.^[18]
Malva linnaei	Cretan Mallow				Naturalised according to FloraBase, though not according to Harvey et al. (2001). The latter source lists this as Lavatera cretica, but this is now a synonym of M. linnaei.^[19]
Malva parviflora	Marshmallow				Naturalised
Sida spodochroma
Mimosaceae
Acacia didyma
Myoporaceae
Eremophila glabra	Tar Bush
Eremophila deserti
Myoporum insulare	Blueberry Tree	27 islands	22 islands	17 islands
Myrtaceae
Eucalyptus oraria	Ooragmandee
Onagraceae
Epilobium billardiereanum	Glabrous Willow Herb
Orobanchaceae
Orobanche minor	Lesser Broomrape				Naturalised
Orchidaceae
Microtis media	Tall Mignonette Orchid
Microtis sp.
Oxalidaceae
Oxalis corniculata	Yellow Wood Sorrel				Naturalised
Papilionaceae
Bossiaea spinescens
Medicago polymorpha	Burr Medic				Naturalised
Medicago sp.					Naturalised
Melilotus indicus					Naturalised
Mirbelia ramulosa
Phormiaceae
Dianella revoluta	Blueberry Lily
Pittosporaceae
Pittosporum phillyreoides	Weeping Pittosporum	10 islands
Plantaginaceae
Plantago coronopus	Buckshorn Plantain
Plantago debilis
Plumbaginaceae
Muellerolimon salicorniaceum		10 islands
Poaceae
Austrodanthonia caespitosa
Austrostipa crinita
Austrostipa elegantissima
Austrostipa flavescens
Austrostipa variabilis
Avena barbata	Bearded Oat				Naturalised
Avena fatua	Wild Oat				Naturalised
Avena sp.					Naturalised
Bromus arenarius	Sand Brome	13 islands	13 islands
Bromus diandrus	Great Brome				Naturalised
Bromus hordeaceus	Soft Brome	11 islands			Naturalised
Bromus japonicus var. vestitus					Naturalised
Bromus madritensis	Madrid Brome				Naturalised
Bromus rubens	Red Brome				Naturalised
Bromus sp.					Naturalised
Cynodon dactylon	Couch				Naturalised
Cynodon sp.
Ehrharta brevifolia	Annual Veldt Grass				Naturalised
Ehrharta longiflora	Annual Veldt Grass		12 islands		Naturalised
Eragrostis dielsii	Mallee Lovegrass
Hordeum murinum subsp. leporinum	Barley Grass				Naturalised; in Western Australia this is treated at species rank as Hordeum leporinum.
Lachnagrostis filiformis	Blown Grass				Harvey et al. (2001) lists this as Agrostis avenacea, but this is now a synonym of L. filiformis.^[20]
Lolium multiflorum	Italian Ryegrass				Naturalised
Lolium perenne	Perennial Ryegrass				Naturalised
Lolium rigidum	Wimmera Ryegrass				Naturalised
Lolium temulentum	Drake				Naturalised
Parapholis incurva	Coast Barbgrass				Naturalised
Pennisetum clandestinum	Kikuyu Grass				Naturalised
Phalaris canariensis	Canary Grass				Naturalised
Phalaris minor	Lesser Canary Grass				Naturalised
Phleum pratense	Timothy			"Gun Islet"	Naturalised
Poa annua	Winter Grass				Naturalised
Poa poiformis	Coastal Poa
Polypogon monspeliensis	Annual Beardgrass				Naturalised
Polypogon tenellus
Rostraria cristata					Naturalised
Setaria dielsii	Diels' Pigeon Grass	16 islands	11 islands
Setaria sp.
Spinifex longifolius	Beach Spinifex	15 islands	13 islands
Sporobolus virginicus	Marine Couch
Triticum aestivum	Wheat				Naturalised
Vulpia myuros	Rat's Tail Fescue				Naturalised
Polygonaceae
Emex australis	Doublegee				Naturalised
Portulacaceae
Calandrinia calyptrata	Pink Purslane
Primulaceae
Anagallis arvensis	Pimpernel				Naturalised
Proteaceae
Grevillea argyrophylla	Silvery-leaved Grevillea
Ranunculaceae
Ranunculus sessiliflorus	Smallflower Buttercup
Rhamnaceae
Spyridium globulosum	Basket Bush
Rubiaceae
Galium sp.					Harvey et al. (2001) list this as "Galium migrans" but, according to FloraBase, that species is not present in Western Australia.^[21]
Opercularia vaginata	Dog Weed
Rutaceae
Diplolaena grandiflora	Wild Rose
Santalaceae
Exocarpos aphyllus	Leafless Ballart
Exocarpos sparteus	Broom Ballart
Sapindaceae
Dodonaea aptera	Coast Hop-bush
Dodonaea inaequifolia		East Wallabi I., Oystercatcher I., West Wallabi I.
Dodonaea viscosa	Sticky Hopbush
Scrophulariaceae
Dischisma arenarium					Naturalised
Solanaceae
Lycium ferocissimum	African Boxthorn				Naturalised. This has been declared a noxious weed, and an eradication program is in place. Harvey et al. (2001) record the plant on only these ten islands, but in 2007 the Department of Environment and Conservation reported that it had been eradicated from 14 out of 18 islands on which it had previously occurred.^[22]
Lycopersicon esculentum	Tomato				Naturalised
Nicotiana glauca	Tree Tobacco				Naturalised
Nicotiana occidentalis subsp. hesperis	Native Tobacco	14 islands
Solanum laciniatum	Kangaroo Apple				Naturalised
Solanum nigrum	Black Berry Nightshade				Naturalised
Solanum symonii
Sterculiaceae
Lasiopetalum angustifolium	Narrow Leaved Lasiopetalum
Tamaricaceae
Tamarix aphylla	Athel Tree				Naturalised. Harvey et al. (2001) list this as "Tamarix sp.", but T. aphylla is the only Tamarix species naturalised in Western Australia.^[23]
Thymelaeaceae
Pimelea microcephala	Shrubby Riceflower	11 islands
Urticaceae
Parietaria cardiostegia
Parietaria debilis	Pellitory			13 islands
Urtica urens	Small Nettle				Naturalised
Zygophyllaceae
Nitraria billardierei	Nitre Bush	43 islands	30 islands	34 islands	This is the most widespread plant species in the Houtman Abrolhos.
Zygophyllum simile

Notes and References

1. Judith M. . Harvey . 2001 . A flora and vegetation survey of the islands of the Houtman Abrolhos, Western Australia . CALMScience . 3 . 4 . 521–623. Data also available in McCrea . Jo . Inventory of the Land Conservation Values of the Houtman Abrolhos Islands . October 2003 . 151 . 0819-4327 . Department of Fisheries . Government of Western Australia . 2008-02-02 . https://web.archive.org/web/20080723020059/http://fish.wa.gov.au/docs/mp/mp151/index.php?0508 . 2008-07-23.
2. Web site: Name Currency — Conyza albida Spreng. . . Department of Environment and Conservation, Government of Western Australia . 2008-02-23.
3. Web site: Name Currency — Pseudognaphalium luteoalbum (L.) Hilliard & B.L.Burtt. . . Department of Environment and Conservation, Government of Western Australia . 2009-01-09.
4. Web site: Name Currency — Senecio lautus Willd. . . Department of Environment and Conservation, Government of Western Australia . 2008-02-03.
5. Web site: Name Currency — Sonchus tenerrimus L. . . Department of Environment and Conservation, Government of Western Australia . 2008-02-23.
6. Web site: Name Currency — Cynoglossum australe R.Br. . . Department of Environment and Conservation, Government of Western Australia . 2008-02-03.
7. Department of Fisheries (Western Australia) . Management of the Houtman Abrolhos System: A Draft Review 2007 – 2017 . Fisheries Management Paper No. 220 . 2007 . 2007-12-01 . 11 October 2007 . https://web.archive.org/web/20071011002001/http://www.fish.wa.gov.au/docs/mp/mp220/fmp220.pdf . dead .
8. Web site: Name Currency — Hymenolobus procumbens (L.) Schinz & Thell. . . Department of Environment and Conservation, Government of Western Australia . 2008-02-04.
9. Web site: Name Currency — Petrorhagia velutina (Guss.) P.W.Ball & Heywood . . Department of Environment and Conservation, Government of Western Australia . 2008-02-24.
10. Web site: Name Currency — Spergularia nesophila L.G.Adams ms . . Department of Environment and Conservation, Government of Western Australia . 2008-02-24.
11. Web site: Stevens, P. F. . June 2007 . Celastrales . Angiosperm Phylogeny Website (Version 8) . 2008-02-22.
12. Web site: Name Currency — Stackhousia viminea Sm. . . Department of Environment and Conservation, Government of Western Australia . 2009-01-04.
13. Incorporation of the Australian genera Halosarcia, Pachycornia, Sclerostegia and Tegicornia into Tecticornia (Salicornioideae, Chenopodiaceae) . Kelly A. . Shepherd . Wilson, Paul G. . 2007 . . 20 . 4 . 319–331 . 10.1071/SB07002.
14. Bryophyllum delagoense (Crassulaceae) : a new weed for Western Australia and a potentially serious problem for the Abrolhos Islands . Longman, Vanda . Harvey, Judith M. . Keighery, G. J. . . 13 . 2 . 399–401.
15. Web site: Name Currency — Isolepis nodosa (Rottb.) R.Br. . . Department of Environment and Conservation, Government of Western Australia . 2008-02-05.
16. Web site: Name Currency — Centaurium maritimum (L.) Janch. . . Department of Environment and Conservation, Government of Western Australia . 2008-02-07.
17. Web site: FloraBase Search: genus:Pelargonium species:zonale . . Department of Environment and Conservation, Government of Western Australia . 2008-02-25.
18. Web site: Name Currency — Malva australiana M.F.Ray . . Department of Environment and Conservation, Government of Western Australia . 2008-02-09.
19. Web site: Name Currency — Malva cretica L. . . Department of Environment and Conservation, Government of Western Australia . 2008-02-25.
20. Web site: Name Currency — Agrostis avenacea J.F.Gmel. . . Department of Environment and Conservation, Government of Western Australia . 2008-02-09.
21. Web site: Name Currency — Galium migrans Ehrend. & McGill.. . Department of Environment and Conservation, Government of Western Australia . 2010-10-28.
22. Web site: African boxthorn eradication close . 2007-07-03 . NatureBase . Department of Environment and Conservation, Western Australia . 2008-02-27.
23. Web site: Search: Genus: Tamarix . FloraBase . Department of Environment and Conservation, Western Australia . 2008-02-23.