Through the selective cross-breeding of common pea plants (Pisum sativum) over many generations, Mendel discovered that certain traits show up in offspring without any blending of parent characteristics. Mendel observed seven traits that are easily recognized and apparently only occur in one of two forms. They are : 1. Flower colour - Purple and white. 2. Flower position - Axil and terminal 3. Stem length - Long and short 4. Seed shape - Round and Wrinkled 5. Seed colour - Yellow and Green 6. Pod shape - Inflated and constricted 7. Pod colour - Yellow and Green