Monocotyledons, also known as monocots, share these features:
They have one cotyledon (leaf in the seed).
The main leaf veins are usually parallel to each other.
Flower parts (Petals, sepals, stamen etc) are usually in threes.
The initial primary root is quickly replaced by adventitious roots forming a fibrous root system.
There is usually no secondary growth.
Pollen grains tend to be bilaterally symmetrical.
Pollen grains have only one pore or furrow.
Vascular bundles are scattered through the stem.