Caffeine Free English Pillow Style Tea Bags That Are Oxygen Bleached, Not Chlorine Treated No Strings, No Staples How It Works: A small branched shrub found mainly in moors, humus-rich soil and open woods from lowland mountains, Bilberry (Vaccinium myrtillus) bears small blue-black, many-seeded berries. Also commonly known as whortleberry, Bilberry has been a source of fresh jam for hundreds of years. Extensively written about in 16th century herbals, this plant is native to northern Europe and Asia; with its nearest American counterpart being the huckleberry. During World War II, Royal Air Force pilots swore that eating Bilberry jam prior to night missions significantly improved their visual acuity in the darkness.