Jamieson and Campbell (1982) theorize how to name, define, and understand the blending of generic features in certain acts. "For our purposes, we shall label such generic blends 'rhetorical hybrids,' a metaphor intended to emphasize the productive but transitory character of these combinations" (p. 147). Jamieson and Campbell do not specify whether the fusion is to result from recurrent elements or is more unique to a particular moment or situation.
Jamieson, K. H. & Campbell, K. K. (1982). Rhetorical hybrids: Fusion of generic elements. Quarterly Journal of Speech 68(2), 146-157.
Jamieson and Campbell's examples are the Congressional eulogies for John F. Kennedy and Lyndon Johnson's Thanksgiving Day eulogy, which combined the classical genres of epideictic, forensic, and deliberative.
Renaissance literary debates about genre mixing used the metaphor of the hybrid.
Emerging Genres class, N.C. State University, Spring 2010, Carolyn Miller