When you start the Key to Tasmanian Dicots, the first thing it asks is which broad group your plant belongs to. For flowering plants that usually means choosing between dicotyledons ("dicots") and monocotyledons ("monocots"). A handful of features, used together, will get you there quickly.
The differences at a glance
| Feature | Dicots | Monocots |
|---|---|---|
| Seed leaves (cotyledons) | Two | One |
| Leaf veins | Net-like, branching | Parallel, running lengthwise |
| Flower parts | In fours or fives (or multiples) | In threes (or multiples of three) |
| Roots | Often a main tap root | Usually fibrous, many similar roots |
| Leaf shape | Often broad, with a stalk | Often long and strap-like |
| Woody growth | Many become shrubs and trees | Rarely truly woody (palms, grass-trees are special cases) |
Looking closer at each clue
Leaf veins are the easiest test
Hold a leaf up to the light. If the veins branch and form a net or web across the blade, you are almost certainly looking at a dicot. If the main veins run side by side from the base to the tip, like the lines on a blade of grass, it is most likely a monocot.
Count the flower parts
Petals, sepals and stamens often come in sets. Sets of four or five (a five-petalled flower, for example) suggest a dicot. Sets of three — three petals, three sepals, six stamens — suggest a monocot. Lilies and orchids are classic "parts in threes" monocots.
Seed leaves and roots
The names come from the seedling: a dicot sprouts with two seed leaves, a monocot with one. You rarely see this in the field, but it underpins the other differences. Dicots also tend to have a single deep tap root, while monocots usually have a spreading mat of fibrous roots.
Tasmanian examples
Dicots include most of the island's familiar trees, shrubs and wildflowers: eucalypts, wattles, banksias, native heaths and daisies. Monocots include the grasses, sedges, rushes, lilies, irises and orchids. So if you have found a flowering shrub or broad-leaved herb, you are usually in dicot territory; a grassy or strappy plant with three-part flowers points to the monocots.
A useful rule, not an unbreakable one
These tests work for the great majority of plants, but nature has exceptions, and modern classification no longer treats the "dicots" as a single natural lineage — some traditional dicots are now known to sit closer to the monocots. That is exactly why a good key checks several features in turn rather than relying on one. When you are unsure, note down everything you can see and let the key do the narrowing.
Ready to identify your plant? Start with the group identifier and family key.
Open the Key to Tasmanian Dicots →Common questions
What is the quickest way to tell a dicot from a monocot?
Look at the leaves. Net-like (branching) veins usually mean a dicot; parallel veins running the length of the leaf usually mean a monocot. Flower parts in fours or fives point to dicots; parts in threes point to monocots.
Are eucalypts dicots or monocots?
Eucalypts are dicots. So are wattles, banksias, daisies and most of Tasmania's familiar trees and shrubs. Grasses, sedges, lilies, irises and orchids are monocots.
Do these rules always work?
They work most of the time, but there are exceptions, and modern classification no longer treats the dicots as a single natural group. For a reliable identification, use several features together and confirm with an identification key.