Abstract
The Chiliotrichum Group sensu lato (Compositae: Astereae) comprises 11 genera and 31 species distributed from Colombia to Tierra del Fuego, and it is composed of four main clades:

1. the Chiliotrichum clade (composed of Aylacophora, Chiliophyllum, Chiliotrichum, and Lepidophyllum),
   
2. the Haroldia clade (composed of Haroldia),
   
3. the Llerasia clade (composed of Llerasia and Ocyroe), and
   
4. the Nardophyllum clade (composed of Cabreraea, Chiliotrichiopsis, Katinasia, and Nardophyllum).

A taxonomic revision is presented for Chiliotrichum, Haroldia, and Nardophyllum clades, which are referred to here as Chiliotrichum Group sensu stricto. The Chiliotrichum Group sensu stricto, composed of 9 genera and 16 species, constitutes the most diverse assemblage of taxa in the Chiliotrichum Group sensu lato. All species in the Chiliotrichum Group sensu stricto were taxonomically evaluated and circumscribed based on analysis of the protologues, laboratory studies, and careful study of nearly all type material, dried specimen collections, and extensive field observations.

Keys for genera in the Chiliotrichum Group sensu lato and species for the genera treated are provided. Also provided for these species are complete synonymies, detailed descriptions, line drawings, photographs of live specimens and their habitat, and distribution maps.

A list of all specimens examined is presented for each species. Three genera are described herein as new: Cabreraea, Katinasia, and Haroldia; and four new combinations are presented: Chiliotrichum fuegianum (O. Hoffm.) Bonif., Cabreraea andina (Cabrera) Bonif., Katinasia cabrerae (Bonif.) Bonif., and Haroldia mendocina (Cabrera) Bonif. One species name is neotypifi ed (Barnadesia lanata Meyen), and six synonyms of accepted taxa are lectotypified. One species, Chiliotrichum rosmarinifolium, is reduced to the synonymy of Chiliotrichum diffusum.