How to Tell a Monocot From a Dicot

Plants that produce seeds are put into two categories: monocots and dicots. This distinction is more than just a bit of scientific trivia. The difference between monocots and dicots has been exploited by manufacturers of weed killers. Their chemicals are made to target dicots, not monocots. Since grass is a monocot and most weeds are dicots, this works out very well for our lawns. Knowing how to tell a monocot from a dicot will let you predict which plants will be affected by your lawn sprays. Read on to learn how to tell a monocot from a dicot.


Instructions

Step 1

Observe the sprouts and look at the cotyledons. The “cot” in monocot and
dicot is short for “cotyledon.” The cotyledon is the “seed leaf” that the
seed puts out when it sprouts. A monocot has a single seed leaf (“mono” means
“one”) and a dicot has two seed leaves (“di” means “two”). This observation
can only be made when the seed is just sprouting.

Step 2

Observe the roots. Monocots have short fibrous roots that stay close to the
surface. Dicots have a long, central tap root that goes deep into the ground.
Dicots may also have other roots, too, surrounding the tap root.

Step 3

Observe the veins in the leaves. The veins in monocots run parallel to each
other, as seen in grass leaves. Monocot leaves tend to be long and narrow.
The veins in dicot leaves branch out like the veins in your hands.

Step 4

Observe the petals of the flowers. Monocot petals come in multiples of three
such as three, six or nine. Dicots petals and sepals come in multiples of
four or five--four, eight and 12 or five, 10 and 15.

Step 5

Observe a cross section of the stem under a microscope. Monocots have their
vascular bundles scattered randomly throughout. Dicots have their vascular
bundles arranged neatly in a circle, as if they were placed on imaginary
spokes coming out of the center.

Step 6

Monocots mainly belong to the grass family of plants. Examples of monocots
are grass, wheat, oats, barley, corn, rice, bamboo, onion, asparagus, lilies,
bananas and palm trees.

Step 7

Dicots are mainly broad leaf trees, ornamental flowers, and fruits and
vegetables. Examples of dicots include maple and oak trees, fruit trees,
grapes, strawberries, daisies, marigolds, roses and garden vegetables such
as tomatoes, squash, beans, peas and potatoes.