This work explores the representation of biological phenomena as stimuli to designers for biomimetic design. We describe a study where participants were asked to solve a micro-assembly problem given a set of biological representations of leaf abscission for inspiration. The visual aids presented to the designers are investigated, and the use of functional models of biological phenomena in particular is critiqued. The designs resulting from the study are classified and theories drawn as to possible influences of the biological representations. Observations, retrospective conversations with participants, and analogical reasoning classifications are used to determine positive qualities as well as areas for improvement in representation of the biological domain. Findings suggest that designers need an explicit list of all possible inherent biological strategies, previously extracted using function structures with objective graph grammar rules. Challenges specific to this type of study are discussed, and possible improvement of representative aids are outlined.