Naming plants:
People usually refer to plants by their common name and most of the time the use of common names for plants is appropriate. However the use of common names can sometimes lead to confusion over plant identity because some plants share common names, some plants have multiple common names and some plants have common names that are only used in particular geographic areas.
Fortunately there is a system of plant naming that may look confusing at first but it greatly reduces confusion over plant identification.
This system is called Binomial Nomenclature and it was first developed in the 1750s Plants are grouped according to shared characteristics and all plants are assigned a botanical name (scientific name) that consists of two latin words.
The first word indicates the genus to which a plant belongs and the second word indicates the species of a plant.
Plants that are in the same genus are closely related and they have similar characteristics. The species name indicates a grouping of plants within a genus that have identical features or close to identical features. Genera that possess similar characteristics are grouped into families.
You will notice in this book that some plants have been given multiple botanical names. This is because taxonomists are constantly refining the relationships between plants, and the recent development of DNA techniques has been particularly helpful in establishing the similarities and differences between groups of plants.
As new information has been discovered, plants may have been allocated to a different genus or to an entirely new genus in some cases. Some species have been split into two or more new species and some groups of species have been combined. The old or alternative names have been included in this book in cases where plants have been recently renamed or in cases where there may still be confusion over a plant’s botanical name.
Each plant described in this book is given the following
naming information:
Common name
(other common names)
Botanical name (other botanical names or older names if applicable) [family]
Example –
Crofton weed
(catweed, sticky eupatorium, Mexican devil, sticky snakeroot)
Ageratina adenophora (also known as Eupatorium adenophorum, Eupatorium glandulosum or Eupatorium pasdadense) [Asteraceae]
Some notes about plant names
The plural of the word genus is “genera”. The word “species” applies to both the singular and the plural but their abbreviations are different.
The singular abbreviation for species is ‘sp’ and the plural abbreviation for species is ‘spp’, so Crotalaria sp is used when referring to a particular unspecified species of Crotalaria and Crotalaria spp is used when referring to several unspecified Crotalaria species or all species of Crotalaria.
It is a plant naming convention to express both the genera and the species names in italics. In this book italics are used for genera and species, except when referring to plants using their genera as a common name. For example: it is appropriate to write both ‘there are several species of Crotalaria in the pasture’ and ‘there are several crotalarias in the pasture’.
In the second phrase ‘crotalarias’ is used as a common name for the plants and italics are not used. This use of genera as a common name without italics is in line with the plant naming conventions of many horticultural societies but not all taxonomists agree with this convention.
Identifying plants:
Poisonous plants do not, unfortunately, have any particular characteristics that indicate their potential toxicity. The identification notes in this book are designed to assist in the identification of potentially poisonous plants. Some of these plants can be easily identified from the notes and from the photos.
Other plants are more difficult to identify and further research may be needed before undertaking any action to either remove or keep particular plants in horse areas.
- It is important to correctly identify plants that are potentially poisonous for reasons that include:
- Mistakes in identification can be dangerous to horses if poisonous plants are mistakenly identified as safe plants.
- Mistakes in identification can result in wasted money,time and effort if safe plants are removed from horse areas on the mistaken belief that they are poisonous.
- Some genera contain both poisonous species and Australian native species that are not poisonous but are vulnerable or endangered. In particular, the genera Indigofera, Swainsona and Crotalaria contain toxic species and non-toxic species that are vulnerable or endangered.
- All of the plants in some genera are considered toxic to horses, for example Solanum and Senecio, however these genera also include Australian native species that are vulnerable or endangered.
- A positive identification of a suspect plant will ensure that the correct management technique is undertaken that will keep horses safe from poisoning and will preserve plants that are vulnerable or endangered.
The avenues through which you can seek help in confirming the identity of a plant include:
-
A reputable gardening or botanical book.
- A reputable website that has information on plant identification
- Knowledgeable staff at nurseries or garden centres.
- A local agronomist.
- Your state Department of Agriculture.
- Your state Herbarium.
- Some of these agencies provide plant identification services and a fee may or may not be charged. It is usually free to use the public reference collections that
some of these agencies provide. You can find out more information on plant identification services by contacting the appropriate agency by phone or via the Internet. The more information that you can gather about a plant, the better your chances of identifying it quickly and accurately. Always collect a sample of a plant to assist in identification and samples can be sent by mail to some agencies.
Plant sample preparation:
- The sample should consist of a small branch or a portion of stem that is around 30 cm long and has leaves, flowers and/or fruit still attached.
- Collect the whole plant if it is small. This is particularly important for grasses.
- Where appropriate, collect tubers or bulbs with all or part of the plant attached. Collect a sample of the roots and the fronds when seeking the identity of a fern.
- Collect a sample of the buds, fruit, young leaves and adult leaves when seeking the identity of a tree. Make a note of information such as the bark type, the size and growth characteristics of the tree and the habitat in which the tree is growing.
- If you are mailing a sample to an agency that offers a plant identification service they will usually want you to provide information that includes the date and location of collection of your specimen as well as details of the habitat in which the plant was growing.
- Samples should be pressed and dried before mailing to ensure that they are not destroyed by mould and that mould does not pose a health risk to the person who opens the package containing your sample. Samples can be pressed between sheets of newspaper. Loose seeds or fruits can be put into separate paper bags or envelopes.
- The pressed and dried plant sample should be packed with cardboard to prevent damage. Samples should not be stuck onto paper.
Toxicity information on poisonous plants:
The information on plant toxins presented in this book is intended to give the reader some background information on how toxins cause poisoning in horses and the signs that might be seen in horses that have ingested plant toxins.
This information may also help the reader when it is necessary to undertake a paddock inspection to locate a plant that may have caused poisoning symptoms in a horse.
The information on the toxicity of plant toxins and the signs that might be seen in poisoned horses should not be used to diagnose or treat a horse that may have been poisoned by the ingestion of toxic plants.
ALWAYS CONSULT YOUR VETERINARIAN IF PLANT POISONING IS SUSPECTED IN A HORSE.
How to find plants in this book
The index containing plant names at the back of this book will make finding a plant of interest easy – if you know its name. If you need to identify a plant that is growing in your paddock the tables on pages 104-108 show plant characteristics that should guide you towards the correct identity of the plant.
Distribution maps
The distribution map alongside each plant description is meant to serve as a general guide to the areas within Australia in which the plant might be found. Underneath most of the distribution maps is a brief note on the type of habitat in which the plant is usually found growing.
Management notes
The management notes presented in this book are intended to serve as a guide to some simple management techniques that can be used to control poisonous plants or to protect horses from exposure to poisonous plants. Some of the practices included in the management notes for particular plants in this book may not represent suitable practice for all horse farms or for all situations.
It is important to seek local expert advice before implementing farm management tasks, particularly when intending to use herbicides or when employing practices that may be detrimental to pastures, the environment or animal health.
Danger icons
The coloured horse icons are meant to serve as a basic guide to the degree of danger that particular plants pose to horses.
Highly dangerous:
Plants with a red icon are those known to be highly toxic to horses, are commonly found in areas where horses are kept and/or they are palatable to horses. Plants that are so toxic that only small amounts of the plant will cause severe poisoning if ingested may also have a red icon.
These plants should always be removed from horse areas or they should be fenced off to restrict horses’ access to the plants. When fencing off highly toxic plants, ensure that horses can’t reach the plant through the fence and that leaves or fallen branches can not end up where a horse might access them. Prunings or clippings of highly toxic plants must never be placed in horse paddocks.
Moderately dangerous:
Plants with a blue icon are those that are known to be toxic to horses but are not commonly eaten, are only toxic under certain conditions, or are not commonly found in horse areas. Plants that do not cause serious poisoning in horses but are commonly found in pastures may also have a blue icon.
These plants should be controlled or completely removed from horse areas. Management practices should be implemented to ensure that these plants do not become the dominant species in pastures.
Mildy dangerous:
Plants with a yellow icon are those that only cause mild and transient poisoning in horses. A yellow icon might also be assigned to those plants that rarely cause poisoning in horses and are not commonly found in horse areas, or to plants that must be ingested in very large quantities before poisoning occurs.
These plants should be controlled where practical and horses should be watched for potential signs of poisoning if the plant grows in horse areas.
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