In their response, the authors mention that with the lower value from Boal and Ng the trichomes collapse into a heap, and so a larger bending modulus was necessary.
Walter (ref 7) describes the formation of “clumps” which are very similar to the structures describes by Shepard. Shepard and Sumner provide better images (Walter only shows sketches), but it might be worth mentioning that the phenomenon is more general. As I recall, Petroff et al. (ref 13) show similar patterns.