When it comes to brambles, the taxonomer, or scientific classifier, has before him a lifetime project. I quote Roland: "The blackberries form a complex group where proper species are almost impossible to define. ... Numerous populations may be found in which the members more or less resemble each other. Some 400 have been named and hundreds more may exist. ... This large genus comprises the cloudberry, dewberry, rasberries and blackberries. The flower has many pistels on a conic receptacle and each ovary forms a small succulent drupelet; the aggregate when mature forms the characteristic thimble like fruit." Roland then proceeds to deal with a number of species of the brambles to be found in Nova Scotia and then refers off to the works of Bailey, Aalders and Hall, and Hodgdon and Steele.
