Life Cycle - Plants (4A)

  • Exploring angiosperms.
  • Comparing monocots and dicots.


  • angiosperm
  • dicotyledon
  • monocotyledon
  • corn and bean seeds (soaked in water 1 day before)
  • iodine
  • peanut
  • knife (not sharp) to cut seeds
  • worksheet

Students compare corn and bean seeds.



Angiosperms or flowering plants are the most dominant group of the vascular plant world. The term angiosperm was devised to describe one of the most definitive elements of flowering plants, namely the enclosure of the potential seeds within a hollow ovary. The angiosperms are considered to be advanced as compared with the gymnosperms and other tracheophytes (plants and trees). Flowering plants occur in a wide range of habitats including both salt and fresh water. The basic food supply of the world is derived from the seeds and fruits of angiosperms (rice, wheat, corn) and fibers, wood, drugs, and other products of great economic value.

The studies by John Ray in the 1700's on the structure of seeds led him to discover the difference between monocotyledon (monocots) and dicotyledon (dicots) plants. There are estimated to be about 165,000 different types of dicots and 55,000 types of monocots.

Monocots have only one cotyledon, dicots have two cotyledons. A cotyledon contains stored food and serves as a food reservoir. Aside from the difference between the seeds of monocots and dicots there are other different structures that separate monocots and dicots. Monocots have long, narrow leaves with parallel veins (such as grasses.) The parts of monocot flowers are arranged in threes or in multiples of three. Dicots have broad leaves with branched veins. The parts of dicot flowers are arranged in fours and fives or multiples of fours and fives. Although the distinction between monocots and dicots is not always as sharp and clear as once thought, it is a useful taxonomic grouping.


  1. In this lab students will differentiate between monocot and dicot seeds. Make sure you soak the seeds in water one day prior to the laboratory session. The directions are written on the lab sheet. Students should be instructed to examine the seeds carefully and to draw exactly what they see.

  2. An endosperm is the nutritive tissue in the developing seeds of angiosperms. A cotyledon is the seed or first leaf of angiosperms and gymnosperms. A bean and a peanut are dicots; corn is a monocot.   


[Back to Life Cycle Grid]  [Back to Plants (4)]