What happens when a pollen grain falls on a stigma?

Karthik saw a cucumber plant in the kitchen garden. He identified two types of flowers-some flowers had a small swollen structure behind them while some did not. He removed all the flowers which did not have the swollen structure behind them thinking that they were of no use.

Which flowers did he remove?

Karthik saw a cucumber plant in the kitchen garden. He identified two types of flowers-some flowers had a small swollen structure behind them while some did not. He removed all the flowers which did not have the swollen structure behind them thinking that they were of no use.

What are the flowers which had a small fruit behind them?