The fruit of certain species of bramble (Rubus); in England, the fruit of Rubus cæsius, which has a glaucous bloom; in America, that of Rubus canadensis and Rubus hispidus, species of low blackberries.
Rubus caesius. The dewberry is a delightful and overlooked fruit. The plant is a low, spreading shrub, like a flattened blackberry, with which the fruit has much in common. It is typically a little softer, a little smaller and a lot juicier, covered with a more obvious bloom than blackberries. If you find it growing on open ground, the fruit can be big enough and plentiful enough to pick abundantly. Use it as you would blackberries.
The Dewberries (Rubus sect. Eubatus) are a group of species closely related to the blackberries. They are small brambles with berries reminiscent of the raspberry, but are usually purple to black instead of red.