C. juncea may refer to:

Canna juncea, a garden plant Carmichaelia juncea, a New Zealand broom Ceropegia juncea, a lantern flower Chionochloa juncea, a tussock grass Chondrilla juncea, a noxious weed Conostylis juncea, a perennial herb Coronilla juncea, a North African plant Crotalaria juncea, an Asian legume