De fluviis

De fluviīs, also called Dē fluviōrum et montium nōminibus et dē iīs quae in illīs inveniuntur 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, Asia Minor, 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.

The work

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.

Authorship

The work is considered pseudepigrapha, meaning written by someone other than the attributed author, Plutarch. It is only preserved by the 9th century codex Palatinus gr. Heidelbergensis 398, which includes a marginal note stating, "This is pseudepigraphic, for the intellectual level and diction are far from the genius of Plutarch. Unless he might be some other Plutarch."

Rivers

Works cited in-text

Some 49 different writers are cited with 65 works between them, including 13 on rivers, 9 on stones, 7 histories, and 12 on international relations. Five are listed as the thirteenth volume on that topic by that author. Based on the titles, there would be at least 204 works by these authors.
In comparison, Plutarch's Alexander, a much longer work, cites around 25 sources by name. The authors cited in De fluviis seem to very conveniently come in rashes of similar syllables, e.g. Ctesias, Ctesiphon, Ctesippus. The text itself is highly repetitive. These facts among others cause scholars to doubt heavily that any of the works and authors cited ever existed.
However, it does provide insight into the mind of a 2nd century Greek writer, shedding some light on what they would have considered legitimate. If the intended genre was parody, then it gives insight on what a writer from the period found humorous.

Author	Books	Chapters
Achelaus	Treatise of Rivers First Book of Rivers First Book of Stones	I, VIII
Agatharchides the Samian	Fourth Book of Stones Phrygian Relations	IX, X
Agatho the Samian	Second Book of Scythian Relations	XIV
Agathocles the Milesian	History of Rivers	XVIII
Agathocles the Samian	Commonwealth of Pessinus	IX
Alexander Cornelius	Third Book of Phrygian Relations	X
Antisthenes	Third Book of Meleagris	XXII
Aretazes	Phrygian Relations	XII
Aristobulus	First Book of Stones	XIV
Aristonymus	Third Book of	XXIV
Aristotle	Fourth Book of Rivers	XXV
Caemaron	Tenth Book of the Affairs of India	IV
Callisthenes	Third Book of Hunting	IV
Callisthenes the Sybarite	Thirteenth Book of Gallic Relations	VI
Chrysermus	History of India Third Book of Rivers Thirteenth Book of Rivers	I, VII, XX
Chrysermus the Corinthian	First Book of his Peloponnesiacs	XVIII
Cleanthes	Third Book of the Wars of the Gods First Book of Mountains	V, XVII
Clitonymus	Third Book of Thracian Relations	III
Clitophon	Thirteenth Book of the Building of Cities	VI, VII
Clitophon the Rhodian	First Book of Indian Relations	XXV
Ctesias	First Book of Rivers	XIX
Ctesias the Cnidian	Second Book of Mountains	XXI
Ctesias the Ephesian	First Book of the Acts of Perseus	XVIII
Ctesiphon	Third Book of Plants First Book of Trees Thirteenth Book of Trees	XIV, XVIII, XXIII
Ctesippus	Second Book of Scythian Relations	V
Damaratus	Third Book of Rivers Fourth Book of Phrygia	IX
Demodocus	First Book of the History of Hercules	XVIII
Demostratus of Apamea	Second Book of Rivers	IX, XIII
Dercyllus	Third Book of Mountains First Book of Satyrics First Book of Stones Third Book of Aetolics	I, VIII, X, XIX, XXII
Diocles the Rhodian	Aetolics	XXII
Dorotheus the Chaldaean	Second Book of Stones	XXIII
Heraclitus the Sicyonian	Second Book of Stones	XIII
Hermesianax of Cyprus	Second Book of his Phrygian Relations	II, XII, XXIV
Hermogenes		XVII
Jason of Byzantium	Thracian Histories	XI
Leo of Byzantium	History of Boeotia Third Book of Rivers	II, XXIV
Nicanor the Samian	Second Book of Rivers	XVII
Nicias Mallotes	Book of Stones	XX
Plesimachus	Second Book of the Returns of the Heroes	XVIII
Sosthenes the Cnidian	Thirteenth Book of Iberian Relations	XVI
Sostratus	Second Book of Rivers First Collection of Fabulous History	II, XXIV
Theophilus	First Book of Stones	XXIV
Thrasyllus	Third Book of Stones	XI
Thrasyllus the Mendesian	Thracian Histories Relation of Egypt	XVI
Timagenes the Syrian		VI
Timagoras	First Book of Rivers	XXI
Timolaus	First Book of Phrygian Relations	IX
Timotheus	Eleventh Book of Rivers Argolica	III, XVIII