O-Berries

O-Berries.
A popular choice for the feeding of many species of animals across the world.
But most common in Rethium and the Histian Empire.
The O-Berry is a very common berry which is grown off of a bacciferous plant which can be found specifically on the islands of the Histian Empire, and which are thought to be exclusive to those islands alone on the planet due to some unknown chemicals or other substances in the soil in that part of the world.
It is a small berry with a circular shape similar to the letter 'O', and which is colored yellow with a small green bud on the top, which is where the berry connects to the growing bush before being removed. 
The O-Berry is extremely high in both protein and potassium, both of these being chemicals that assist with the bodies natural growth process and as a natural source of energy for those processes. It is not just a common food for pets like Piffles and other animals, the former of whom favor the berry as their primary source of nutrition for their entire lives, but Humans and other races are able to feed on this berry as a part of their daily diet.
The O-Berry is also a common source of yellow dye, and is primarily grown in the Histian Empire in massive farms that cover acres worth of land where thousands of these berries are grown, although their primary season is springtime, all throughout the months of March, April and May.