To use this guide first determine the symmetry of the unknown flower. Is it radially symmetrical (looks the same when rotated - like a daisy), bilaterally symmetrical (the right IIDe is a mirror image of the left - like a face), or does it show no symmetry, either because the flower is irregular or is too small to tell? Flowers in this guide are arranged in these 3 groups; radially symmetrical, bilaterally symmetrical, and having no obvious symmetry.
If a flower falls in the radially symmetrical group, count the number of petals and read the brief descriptions of flower families having that number of petals. Decide which ones are most like the flower in question, and look through the pictures of flowers in those families. If any seem similar read the description to see if there is a match. If none look promising, turn to the section of families with a variable number of petals, and follow the same procedure.
If a flower is bilaterally symmetrical, look at the descriptions of families of flowers with that type of symmetry, and proceed as before.
Follow the same procedure with non-symmetrical flowers.
In each group families are arranged in descending order of number of species in the family pictured in this guide, and the number of species is in parentheses.