Nutlet micromorphology and character evolution of Lappula species (Boraginaceae) and its systematic implications.

The results show that the nutlet ultrastructure pattern of Rochelieae is systematically informative at the genus level, but not at the species level. Findings demonstrated that glochid is not an ancestral trait but is a synapomorphy and the transition to this trait occurred in the genus Lappula. The close boundary of nutlet microstructures between L. barbata and L. microcarpa has been discussed.