De fluviis

Dē fluviīs (Latin for "concerning rivers"), also called Dē fluviōrum et montium nōminibus et dē iīs quae in illīs inveniuntur ("concerning the names of rivers and mountains and those things which are found in them") or the Greek Περὶ ποταμῶν καὶ ὀρῶν ἐπωνυμίας, is a Greek text by Pseudo-Plutarch written during the 2nd century CE. It discusses twenty-five rivers in Greece, Turkey (called Asia), India, Gaul, Egypt, Scythia, and Armenia. The chapters typically start with a myth about the river, include information about local flora and stones, and end with details about a nearby mountain.

Scholars today classify it as paradoxography, or even a parody of paradoxography.

Notably, Pseudo-Plutarch describes 22 of the 25 rivers as deriving their names from people who committed suicide in them. Six of the rivers were renamed twice due to suicide. Several of the mountains are also said to have gotten their names from suicides.

Most of the plants and stones described have mystical qualities to them, from warding off spirits and gods, to causing and healing madness, to exposing liars and thieves.

Sources are cited throughout the book including the Treatise of Rivers by Achelaus, the Second Book of Rivers by Sostratus, the Third Book of Mountains by Dercyllus, the Third Book of Plants by Ctesiphon, and the History of Boeotia by Leo of Byzantium. A full list is given below.