Deleuze and Guattari's principles of the rhizome were used to inform the design of a massive open online course (MOOC), "Rhizomatic Learning: The Community is the Curriculum," which came to be known as Rhizo14. In a previous paper about learner experiences in this course our reported findings from a qualitative survey (which enabled anonymous responses) raised concerns about the ethics of using experimental pedagogies in designing MOOCs. In this paper, we continue this research and report learners' understandings of the rhizome as applied in Rhizo14, from what participants have told us in email interviews and from our own reflections on participation in the course. Our findings reveal that many participants could relate to and welcomed the anti-authoritarian, anti-hierarchical characteristics of the rhizome, but that knowledge and understanding of Deleuze and Guattari's conceptual principles of the rhizome was more difficult. Lack of engagement with theory and lack of appreciation of the incompleteness and complexities of the rhizome metaphor can result in negative consequences, such as imbalances in power relations and increased vulnerability for some learners.