How to Identify Flowers by Category


Botanists classify plants by the ways in which their flowers are structured: the number and shape of petals, shape and placement of the sepals (leaf or petal-like parts usually found below the petals) and the way the female and male parts of the plant, pistils and stamens, are arranged. While it would take a course in botany to identify each flower definitely, there are many categories with fairly obvious characteristics.

Step 1

Count the petals. If they are in multiples of three, you have a "monocot" a member of the lily class. If they are in multiples of five, or have many petals, go to Step 3. If there are one or two stamens, you have a member of the orchid family. If more, go on to Step 2.

Step 2

Count the stamens, using a magnifying glass or hand lens. If there are six stamens, you have a member of the lily family. This includes trilliums, fritillarias, asparagus, camas and erythroniums, as well as lilies. If only three, it is a member of the iris family, which includes the genus Sisyrinchium (blue-eyed grass) as well as irises.

Step 3

Decide whether or not your flower is in the daisy family, the Compositae. This is one of the largest plant families and is characterized by having a disk made up of tiny individual flowers without petals, surrounded by "ray flowers," each with a large petal, the whole group of them combining to give you a daisy shape. This group includes chrysanthemums, feverfew, rudbeckia, echinacea, sunflowers and, of course, shasta daisies.

Step 4

Decide whether or not your flower is in the legume family, the Leguminosae. These have distinctive pea-type flowers with a flat petal at the top, often called a "standard," two side petals called "wings" and two petals that have been fused together to form a "keel" at the bottom.

Step 5

Count the petals again. If you have only four, chances are your flower is a member of the mustard family, the Cruciferae. These include dame's rocket, broccoli, money plant and wallflowers.

Step 6

Look at the shape of the flower cluster to see if your "flower" is actually a group of tiny flowers. If it is flat on top, with each flower having a stem of a different length, a shape called an "umbel," chances are you have a member of the celery family, the Umbelliferae. These include many edibles, celery, astrantia and angelica among them, as well as the poisonous water hemlock. Still haven't identified your plant? Many ornamentals have rather ordinary looking flowers, especially those in the rose family. Taking a specimen to your local nursery may be the best next step.

Tips and Warnings

  • Flower identification is a complex skill, so don't expect too much of yourself. Go slowly, learn a few families at a time and keep looking closely at all the flowers you find.

Things You'll Need

  • Flower
  • Magnifying glass or hand lens


  • Flower Identification
  • Plant Families Photo Gallery
  • Flower Structure and Function

Who Can Help

  • Flower Identification: Family Index
Keywords: flower identification, plant families, parts of flowers, flowers by category, categories of flowers

About this Author

Over the past 30 years, Mara Grey has sold plants in nurseries, designed gardens and volunteered as a Master Gardener. She is the author of "The Lazy Gardener" and "The Complete Idiot's Guide to Flower Gardening" and has a Bachelor of Science in botany.