The least known wood is categorized as wood species that have not been used and included into commercial timber classification. The anatomical and fiber quality characterization of the least known wood is important to complete the database for wood identification and assess the quality of fiber for pulp and paper material. In this study, the anatomical properties and fiber quality of wood were observed. The wood samples were provided by Xylarium Bogoriense which belongs to three families namely Icacinaceae (Apodytes sp.), Cardiopteraceae (Citronella spp., Gonocaryum spp.), and Stemonuraceae (Gomphandra sp., Medusanthera papuana, and Urandra sp.). The observation on general characteristics of macroscopic features was conducted using magnification lens. The permanent slides of thin sliced wood samples were obtained following Sass. The anatomical characterization was described according to IAWA Committee. Fiber maceration was undertaken to measure fiber dimensions and determine fiber quality for pulp and paper materials. The results showed that in Icacinaceae family, the diagnostic characteristics of Apodytes sp. were thick-walled fiber cells, ray composition procumbent, square and upright cells mixed throughout the ray. In Cardiopteraceae family, Citronella spp., wood had two distinct sizes of rays, axial parenchyma diffuses, diffuse in-aggregate, and scanty paratracheal. Two different wood species were identified under Gonocaryum genera. Lastly, in Stemonuraceae, Gomphandra sp. and Medusanthera papuana were almost similar macroscopically and microscopically, except in the type of crystals. The diagnostic features of Urandra sp. were axial parenchyma diffuse, uniseriate and all square rays cells. The fiber quality of all samples were categorised into class III for pulp and paper raw material.