After crossing tall and dwarf pea plants, Mendel obtained the F2 generation by

1. The first cross between tall and dwarf gave an F1 generation that was all tall. 2. To see what the F1 carried hidden, Mendel self pollinated those tall F1 plants. 3. The resulting F2 generation showed both tall and dwarf plants. 4. That reappearance of the dwarf trait is what revealed the recessive factor. 5. Crossing F1 with the recessive parent would have been a test cross, a different experiment. _Source: syllabus Biology Ch4 'Principles of Inheritance and Variation'_