Pteridophytes and lycophytes from Osomba Hills, Cross River National Park, Nigeria

Abstract

Pteridophytes and lycophytes from Osomba Hills, a biodiversity hotspot in Nigeria, were collected using a transect method. Floristic sampling was done in six 100 m transects and elevation range of 170 m – 405 m above sea level where each transect consisted of five 10 m × 10 m quadrats spaced 10 m apart. Fieldwork was performed during the dry (February) and wet seasons (July) in 2022. F ifty species from 22 genera in the nine families Adiantaceae, Aspleniaceae, Cyatheaceae, Dennstaedtiaceae, Hymenophylaceae, Polypodiaceae, Pteridaceae, Schizaeaceae and Selaginellaceae were recorded. The lycophytes were represented by only one family, the Selaginellaceae, while the remaining eight families are pteridophytes. The family with the highest number of species was Polypodiaceae (21), while Cyatheaceae and Schizaeaceae recorded only 1 species each. Nine species were collected only in the dry season while 20 species were collected during the wet season. The remaining 21 species were identified in both dry and wet seasons. T he tree fern Alsophila camerooniana (Hook.) R. M. Tryon and the three species of Hymenophyllaceae were limited in range of occurrence. The diversity of these ferns was significant (P<0.05) within Osomba Hill. This variance was typified along latitudinal and temporal scales. The conservation status of 47 species were categorized as ‘Not Evaluated’. A comprehensive evaluation of the conservation status of these plants is recommended to enable the implementation of an appropriate conservation strategy by the management of the park.