Taxonomic revision of the threatened fern genus Cyrtomium C. Presl from the Hazara division, Khyber Pakhtunkhwa, Pakistan

Abstract

The fern genus Cyrtomium C. Presl (Dryopteridaceae) represents an important component of forest understory vegetation in temperate and subtropical regions. However, information regarding its diversity, distribution, and taxonomic status in northern Pakistan remains limited. The present study aimed to conduct a taxonomic revision of Cyrtomium species occurring in the Hazara division of Khyber Pakhtunkhwa, Pakistan, in order to clarify their morphological characteristics, distribution patterns, and conservation status. Extensive field surveys were conducted across 38 localities in the study area, and collected specimens were examined using standard taxonomic and morphological approaches. Diagnostic characters such as rhizome scales, frond morphology, pinna structure, venation patterns, and reproductive features including sori, sporangia, and spores were carefully analyzed to delimit species. The study documented three species of Cyrtomium: C. macrophyllum, C. caryotideum, and C. anomophyllum. These species were recorded from only eight localities (21%) of the surveyed sites, indicating that the genus is sparsely distributed in the region. The species were mainly associated with cool, moist, and shaded habitats within the herbaceous layer of foothill forests, often growing on rocky substrates and near water sources. Comparative measurements of sori, sporangia, and spores, along with diagnostic morphological features, facilitated reliable species identification. A taxonomic key and detailed descriptions were prepared to assist in accurate identification of the species. Furthermore, C. falcatum, previously reported from the region, was excluded from the native flora based on recent taxonomic clarification. The results indicate that Cyrtomium species in Hazara division are rare and threatened by habitat loss, highlighting the need for conservation.