Fungal communities were isolated from surface sterilized leaf segments of nine ethnopharmaceutically important medicinal herbs collected from the Bhadra River Project Area, the Malnad region, Southern India. A total of 2159 isolates belonging to 55 different fungal species were isolated from 3600 leaf segments collected during the wet and dry seasons. Chaetomium globosum (7.3%), Aureobasidium pullulans (6.1%), Cladosporium cladosporioides (3.9%), Curvularia lunata (1.9%), Nigrospora oryzae (1.7%), Alternaria alternata (1.3%), Botryosphaeria subglobosa (1.1%), Phoma multirostrata (0.9%), Aspergillus niger (0.8%), Fusarium oxysporum (0.7%), Rhizoctonia solani (0.4%), and Sphaeropsis sapenea (0.3%) were the most frequently isolated fungal species. Colonization rates of fungal species varied significantly between the two seasons. Host specificity was observed in some host plants.Key words: diversity, fungi, medicinal herbs, seasonality, Malnad Region Plant and microbial symbiotic interactions and how these interactions influence plant communities and environments have been well explored 6,10,22) . Rhizospheric and mycorrhizal associations play a major role in physiological and biochemical properties owing to the growth and ecological fitness of hosts 15) . Microbes like bacteria and fungi which live inside healthy plant tissues without causing apparent symptoms, known as endophytes 33) are also known to form mutually beneficial relationships with their hosts 23) . Being mutualists, these microbial populations are known to be beneficial to host plants by enhancing the absorption of soil nutrients such as phosphorus and other inorganic elements, nitrogen-fixing efficiency 38,43) and plant growth with the production of hormones like auxins, abscisins, ethylene, gibberellins, and kinetins 20,29) . They provide protection to their hosts against insect pests 27) , herbivores 11) , and microbial pathogens 39,42,44) . Fungi present in healthy tissues of plants can promote the invasion of host plant communities with greater species diversity 37) and alter the nutrient cycle in individual plants 18) and in ecosystems 24) . The isolation and characterization of fungal communities will help us to estimate the diversity of fungi 2) , since the true scale of fungi is open to debate 21,26) . Most importantly, fungi isolated from healthy tissues may be a source of various secondary metabolites, alkaloids, and biologically active compounds 35,45) . Bacterial endophytes have been screened from many agricultural, horticultural and forest plant species 1,23,25,28) . In India, medicinal plants have long been used in the ailment of various diseases. In view of the importance of microbial populations which live inside healthy plant tissues, we investigated the distribution of fungal communities and seasonal colonization patterns in medicinal herbs of the Malnad Region, Karnataka state, Southern India. Materials and methods Sample collectionThe leaf samples of Catharanthus roseus India, which is a part of the Western Ghat region, a hot spo...