The Collaborative International Dictionary of English v.0.48:

Incubous \In"cu*bous\, a. [From L. incubare to lie on.] (Bot.)
   Having the leaves so placed that the upper part of each one
   covers the base of the leaf next above it, as in hepatic
   mosses of the genus Frullania. See Succubous.
   [1913 Webster]