T	his book describes and illustrates plant species that are weeds in Western Australia. Most of them have been introduced to the State, but a few are native plants that have expanded their ranges as a result of human activity or have become weeds of cultivation.

In the main part of the text the weeds are listed under four major groups: Ferns - Gymnosperms (conifers) - Monocotyledons (lilies, grasses, sedges) and Dicotyledons (other flowering plants). Within each group, the plants are organised into botanical families that are arranged alphabetically, and within each family the weeds are arranged alphabetically by their genus and species names. A list of introduced species that are doubtfully naturalised is included as Appendix B. Most of the common or more noticeable species have been illustrated. The descriptions concentrate on the characters that distinguish a species from closely-related ones, but also include distribution information, flowering time and region of origin. It should be possible to identify most of the species using this information, but within some groups of related species (such as sedges) it is very difficult to identify individual species with certainty, and the reader is referred to specialist texts that are listed in Appendix C. A glossary of botanical terms will be found at the rear of the text.

Cape tulip in a paddock near York. PH

 Identification and collection of weed specimens

By referring to the illustrations and descriptions in this book, it will be possible to identify most of the weeds found in most parts of the State. Garden centres and agricultural retailers can also help identify many common weeds. Sometimes, however, weeds will be found that can not be identified this way, because they are not illustrated or described, or because they might be new to the State. If you are still unable to identify a particular weed, it might be necessary to collect a specimen of a plant for exact identification. A piece containing flowers, fruits and leaves is most helpful, and it should be the size of a newspaper page and pressed under weight (or several specimens to make up the page if it is a small plant). Press two specimens, one for sending to an expert, and one to be retained by you. Make notes - as detailed as possible - about each specimen. Contact the Weed Science group of Agriculture Western Australia (if the weeds are from agricultural or pastoral land) or the Agwest Garden Advisory Centre (if a garden weed) - a small fee for service may apply for identification and further information. Over 30 local herbaria exist in Western Australia, run by community volunteers, and most will be delighted to help you with identification. These local herbaria will liaise with the Weed Science group and the Western Australian Herbarium in Perth on your behalf, and will keep your specimen as a permanent record of plant distribution in the local area.

 Weeds from agricultural and pastoral land should be identified through Agriculture Western Australia; take the specimen to their nearest office.

 Please note that regulations regarding plant collection apply, and a licence may be necessary. Consult the Department of Conservation and Land Management for details.

 A note on the taxonomy

Giving accurate names to living things is called taxonomy. A plant is first classified into a family (e.g. Asteraceae, the daisy family), then into a genus that has a Latinised name starting with a capital letter (e.g. Helianthus, the sunflower genus) and finally into individual species which are indicated by the second Latinised name (e.g. Helianthus annuus, sunflower and Helianthus tuberosus, Jerusalem artichoke). In botanical texts this name is followed by an abbreviated version of the name of the botanist who first described the plant (e.g. Helianthus annuus L. that stands for the Swedish naturalist Linnaeus, 1707-78). The name of the botanist is omitted from this book, as being irrelevant to most readers.  Ongoing taxonomic research sometimes causes names to be changed. Where this has happened recently, the name formerly applied to that plant is given in brackets. Photographs, taxonomy and textual information are based on specimens contained within the Western Australian Herbarium, and are as correct as the authors can determine at the time of going to press.

Ground layer dominated by weeds: lupins, sousob, cornflag and wild oats, Gooseberry hill. PH

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