Solanum dulcamara is a member of a group of about 50 species called the Dulcamaroid clade.
Solanum dulcamara is most similar to Solanum.lyratum a species found growing in China and Japan.
The leaf shape of Solanum dulcamara is extremely variable. This variation has meant many species names, synonyms, have been given to the same plant.
The plant has purple flowers with strongly turned back, reflexed petals, each with a small green and white dot near the centre of the flower.
The anthers are bright yellow and held tightly together in a cone shape - a glue-like secretion is responsible for this tightness. Mutant plants that do not produce the glue have anthers that spread apart. (Glover, 2004).
The fruits are bright red when ripe and although not as poisonous as Atropa belladonna deadly nightshade they do contain poisonous alkaloids and should not be eaten.
For a detailed species description taxonomy with synonymy see Solanaceae Source