Phanerograms section is one of the important sections of NHPL which conducts research activities mainly on flowering plants viz. Angiosperms and Gymnosperms from different parts of the country. Herbarium specimens of different plant species are collected and then pressed, dried, mounted, identified and arranged according to accepted system of classification. Herbariums are national treasure and reference Centres for plant research. About 1,65,000 herbarium specimens and 106 Type specimens are arranged according to Bentham & Hooker’s system of classification for family, while genera and species are arranged alphabetically.
In 1976, Catalogue of Nepalese Vascular Plants had been published in three Volumes (Catalogue of Nepalese Flowering Plants Vol-1,2,3) in 2010, 2011 and 2012 respectively; which includes the brief information about distribution of plant species preserved in the Herbarium. In 2015, Catalogue of Nepalese Flowering Plants Supplement 1 has been published. It is estimated that about 6,500 species of flowering plants are found in Nepal. Among them, about 82% (4,543) of flowering plants are preserved in this section.