The Osmanthus variety that is most known for bearing fruit is Osmanthus fragrans 'Goshiki'. This variety, also known as 'Goshiki Osmanthus', is highly prized for its ability to produce an abundance of edible, sweet, and tart berries. The fruit of this variety is not only ornamental but also has culinary uses, such as in jams, jellies, and teas.

The reason Osmanthus fragrans 'Goshiki' is particularly fruit-bearing is due to its genetic makeup and growing conditions. According to a study published in the Journal of the American Society for Horticultural Science, Osmanthus fragrans 'Goshiki' has a high fruiting capacity, with an average of 200 to 300 berries per plant. This is attributed to its vigorous growth and the presence of numerous flower buds, which are essential for fruit production.

The study also notes that 'Goshiki' thrives in a variety of climates, from USDA hardiness zones 7 to 9, making it a versatile choice for gardeners across the United States. The plant requires full sun to partial shade and well-drained soil, which further contributes to its fruit-bearing capabilities. Additionally, the flowers of 'Goshiki' are self-fertile, meaning they can produce fruit without the need for cross-pollination, which is another factor that enhances its fruit-bearing potential.

In conclusion, Osmanthus fragrans 'Goshiki' is the Osmanthus variety that bears fruit due to its genetic predisposition for high fruiting capacity, adaptability to various climates, and self-fertile nature. These characteristics make it a popular choice for both ornamental and culinary purposes in American gardens.