A Gram-stain negative, rod-shaped and non-endospore forming bacterium, designated strain YG4-6(T), was isolated from Polytrichastrum formosum collected from Gawalong glacier in Tibet, China and characterized by using a polyphasic taxonomic approach. The predominant fatty acids of strain YG4-6(T) were identified as iso-C15:0 (29.3 %), summed feature 3 (C16:1 ω7c and/or C16:1 ω6c as defined by MIDI, 23.5 %) and iso-C17:0 3-OH (16.5 %). The major polar lipids were found to consist of five unidentified aminolipids and three unidentified lipids. Strain YG4-6(T) was found to contain MK-6 as the dominant menaquinone and the G+C content of its genomic DNA was determined to be 37.3 mol%. The phylogenetic analysis based on 16S rRNA gene sequences showed that strain YG4-6(T) is affiliated to Chryseobacterium species, and its closest related species were Chryseobacterium aahli T68(T) (97.9 % sequence similarity), Chryseobacterium zeae JM-1085(T) (97.8 % sequence similarity), Chryseobacterium yeoncheonense DCY67(T) (97.6 % sequence similarity) and Chryseobacterium soldanellicola NBRC 100864(T) (97.2 % sequence similarity). However, the DNA-DNA relatedness values between these strains and strain YG4-6(T) were found to be clearly below 70 %. Based on the phylogenetic inference and phenotypic data, strain YG4-6(T) is considered to represent a novel species of the genus Chryseobacterium, for which the name Chryseobacterium polytrichastri sp. nov. is proposed. The type strain is YG4-6(T) (=CGMCC 1.12491(T) = DSM 26899(T)). An emended description of the genus Chryseobacterium is also proposed.