Thamnoseris is a genus of plants in the dandelion tribe within the daisy family. There is only one known species, Thamnoseris lacerata, commonly known as the pachycaul tree. It is endemic to the Desventuradas Islands in the South Pacific, part of the Republic of Chile.
Species taxanomy provided by GBIF Secretariat (2022). GBIF Backbone Taxonomy. Checklist dataset https://doi.org/10.15468/39omei accessed via GBIF.org on 2023-06-13; License: CC BY 4.0