We address the character and positioning of Rosennean complexity in hierarchical models of Nature. Thebest form of hierarchical representation of Natural systems is a model hierarchy, whose character wepresent. The complexity which appears between adjacent organizational levels in a model hierarchyperforms the function of a locally-scaled ecosystem related to von Uexk{\"u}ll{\textquoteright}s umwelts. We position Rosen{\textquoteright}s(M,R) model in a model hierarchy as a basic inter-level coupling mechanism.{\textcopyright} 2017 Elsevier B.V. All rights reserved.