Pollen is produced in the stamen in angiosperms and is produced in the microsporangiate cones in gymnosperms. The cones that pollen is produced in are usually referred to as male cones or pollen cones.
In any type of flower, whether it is angiosperm or gymnosperm, pollen is produced and it is a process of the sexual reproduction of a flower. Since plants cannot physically move themselves to reproduce, they are dependent on different elements to help them reproduce. The pollen of the male flower can be taken to a female flower through the air and through the use of bugs, although neither of these are very successful and very few grains of male pollen ever reach a female flower.
Insect pollinated plants are the most successful type of pollinated plants and have the highest rate of male pollen reaching the female plant. This process is done through insects, mostly bees, and does not leave a lot of pollen in the air.
People who get allergic reactions to pollen in the spring or other high production months generally have symptoms that are caused by wind-pollinated plants. When a plant is pollinated through the air, the pollen travels through it to reach the female plant. This pollen can be going through the air or sitting on plants and will cause the allergies that many people experience.