Angiosperms are a diverse phylum of plants, but they are divided into two separate groups called monocots and dicots. Monocots consist of about a quarter of the angiosperms on Earth while dicots make up the rest of the species. But how can someone tell the difference between the two?
If the seed of an angiosperm is opened, the embryo inside will show if the plant is a monocot or a dicot. Scientists tell the difference depending on how many cotyledons there are in the embryo of the seed. Cotyledons are the one or two leaves within the seed. Monocots only have one cotyledon, while dicots have two.
Fortunately, there are ways to tell the difference between monocots and dicots that do not include destroying the plant. Observing the veins in a plants leaves will show what angiosperm it is. If the veins are parallel with each other, then the plant is a monocot. A banana tree is an example of a monocot with parallel veins in their leaves. Dicots have a veins traveling through their leaves in a net like fashion. Oak trees are an example of a dicot.
The stems of plants also gives details about what plant it is. Cutting open one of the stems of a monocot, the vascular tissue will be scattered throughout the stem. However, the vascular tissue will be arranged in a ring, within the stem of a dicot. This may be difficult to discern with many plants, however, if a microscope is not available.
There is a stark difference in the root systems of monocots and dicots, as well. Monocots have a fibrous spread out root system with no main taproot. On the other hand, dicots have a main taproot present. Carrots are easily discernible as a dicot, since humans eat the main root of the plant.
Another way to tell the difference, if a microscope is handy, is to look at the pollen of the plant. Pollen grains of monocots will have one opening, while pollen grains of dicots will have three openings. Most grasses have pollen grains with one opening, which make them monocots.
Looking at the flower of an angiosperm is the easiest way to tell the difference between monocots and dicots. Monocots have flower petals that are usually in multiples of three. If a flower has three, six or nine petals, it is a monocot. Dicots, however, have flower petals in multiples of four or five.