This article explores the diagram found on the recto side of Pierpont Morgan, M. 982, a single leaf from a twelfth-century manuscript held by the Morgan Library and Museum in New York, and believed to originate in the scriptorium of Saint Peter's Abbey in Salzburg, Austria. The diagram represents knowledge as an 'ecodiagrammatic' pattern, depicting the relationship of hierarchical organisms through a fluid cascading system. Spanning riparian, fluvial, and corporeal symbolism, the diagram represents knowledge as a process of expanding categories from unitary source to manifold destinations. Furthermore, it demonstrates the ecological nature of typology, with multiple forms of ecological diagram merging to form a broad ontological pattern spanning metaphysical hierarchies. Pierpont Morgan, M. 982 is a manuscript fragment held in the collection of the Morgan Library and Museum in New York, formerly known as the Pierpont Morgan Library. 1 Within the intricate illustrations of its recto and verso, we are presented with a vision of the Seven Liberal Arts that mingles figurative human representation, a diagrammatic, abstract representation of knowledge as a river, and the personified agency of learning within medieval intellectual culture. Labelled within the library's collection as 'Philosophy nourishing the Liberal Arts, with Arithmetic, Astronomy, Music and a fourth art instructing', M. 982 is a single leaf excised from a larger manuscript. Described by its curators as an illustration in Romanesque style from the monastic scriptorium of St Peter's Abbey in Salzburg, Austria, the M. 982 leaf is thought to have been created during the second third of the twelfth century, c. 1133-1165. 2 If this provenance is correct, M. 982 was the product of a wellestablished and influential node of manuscript production within the oldest 1 Hereafter M. 982. All references to 'M. 982' pertain to the recto, unless specifically stated otherwise. This essay is a modified and expanded version of a chapter from my doctoral thesis, 'Water as Medieval Intellectual Entity: Case Studies in Twelfth-Century Western Monasticism' (unpublished PhD thesis, University of Western Australia, 2014). I would like to thank Parergon's anonymous referees and my thesis examiners, Ellen Arnold, Megan Cassidy-Welch, and Veronica Strang, for their feedback. Unless noted otherwise, all translations are my own.