Question

What will happen if a pollen of one flower falls on flower of another species? Will it reproduce?

Answer 1

If the pollen of one flower falls into the flower of another plant of a different species, then it may or may not produce a new species of plant. It depends upon the conditions of how strong or modified is the flower of  another plant in which the pollen falls on. Therefore it is unpredictable if the plant can reproduce a new species

Answer 2

if the pollen grain of some species fall on the other species it will not reproduce
both the plants the plant whose pollen grain was ransferred an the plant for whom it was transferred should be of he same species only then it will reproduce