Reassessment of Treubia species (Marchantiophyta: Treubiaceae) in New Zealand
Glenny, David; Bulman, Simon; Tremblay, Susan
Treubia belongs to the Haplomitriopsida, a small class of deeply divergent liverworts with an ancient fossil record. Treubia is a genus of interest for having an unusual endophytic fungal association and in having single large oil-bodies in some of the cells whose size and frequency are taxonomically useful. The taxonomy of Treubia in New Zealand has been uncertain and between two and four species have been suggested to be present. DNA sequences and morphology confirm that there are two species of Treubia in New Zealand, Treubia lacunosa and T. pygmaea. The two can be separated morphologically using a combination of shoot width, differences in frequency and size of oil-body cells, presence or absence of gemmae, and differences in habitat. The frequency of oil-bodies in leaf cells alone is insufficient to distinguish the two. New comprehensive descriptions of both New Zealand species are provided, and Treubia lacunosa is re-neotypified. Treubia lacunosoides is a new synonym of T. lacunosa. Treubia tasmanica, which is found in Tasmania, Australia, was confirmed to be morphologically indistinguishable from T. pygmaea but was found to have consistent and significant plastid DNA sequence differences to the New Zealand species.