There is a great deal of confusion between marjoram and oregano. They are related plants, but are two different species. They also taste similar, although oregano often has a stronger flavor, and both contain high amounts of antioxidants. To make it even more confusing, cretan oregano, O. onites, is also called French or pot marjoram and Greek oregano, O. vulgare, is often called wild marjoram.
Cylinder choke is an unconstricted barrel. The shot pattern spreads quickly. Improved Cylinder choke has a slight constriction. It allows the shot pattern to spread fairly quickly. This is a good choice for quail, rabbits, and other upland game. Modified choke has moderate constriction. The shot stays together longer, making the pattern denser and more useful at longer ranges. This choke is used often for dove hunting and is the preferred choke when using steel shot to hunt for ducks or geese.
While less useful for all-around use than more open chokes, there are times when Improved Modified is a good choice. As a rule, and depending on the load used, Improved Modified will extend range by five to 10 yards over Modified with some loads and yet at closer ranges it is easier to hit with than Full choke. When hunting with a side-by-side or over-under double, I often use Improved Cylinder in one barrel and Improved Modified in the other.