The present study explored plant biodiversity, life form, leaf size spectra, and phenology of the Bajaur Agency, KP, Pakistan flora during 2020-2021. A total of 122 plants were collected belonging to 48 families. There were two flowering seasons: 107 plant species (87.70 %) flowers from March to August and 15 plant species (12.29 %) from August to onwards. The dominant families were Asteraceae with 16 spp. (13.3 %), followed by Lamiaceae with 10 spp. (8.1 %), Fabaceae 8 spp. (6.55 %). Brassicaceae, Euphorbiaceae, and Plantaginaceae 6 spp.  (4.91 %) each. Solanaceae 5 spp. (4.09 %), Amaranthaceae, Moraceae, and Poaceae with 04 spp. (3.27 %) each. Polygonaceae with 03 spp. (2.46 %) each. The remaining 38 families have either 2 spp. or less than that. Life form was dominated by therophytes with 65 spp. (53.27 %), followed by megaphanerophytes 13 spp. (10.65 %), mesophenerophytes 05 spp. (4.09 %), hemicryptophytes, chamaephytes and nanophanerophytes 10 spp. each (8.19 %). Phanerophytes, geophytes and cryptophytes 03 spp. (2.14%) each. Leaf spectra of the region were dominated by microphylls with 53 spp. (43.44 %) followed by nanophylls with 31 spp. (25.40 %). leptophylls 20 spp. (16.39 %), mesophylls 15 spp. (12.29 %) and macrophylls 03 (2.45 %). The main aim of this study was to document the biological spectrum, leaf size spectra, and phonological behavior of species in the study area which will be helpful for further researchers such as conservationists, ecologists, and foresters, etc.

Index terms- Plant biodiversity, biological spectra, leaf size spectra, phenology, Bajaur district Pakistan