Taxonomy and Molecular Phylogeny of Ganoderma tropicum (Jungh.) Bres.: A New Record from Thiruvananthapuram District, Kerala, on a Previously Unreported Host, Artocarpus hirsutus (Lam.).

Ganoderma tropicum (Jungh.)Bres., a laccate polypore fungus with considerable ecological and medicinal significance, is widely distributed across tropical Asia.In the course of a systematic survey of poroid fungi in Thiruvananthapuram District, Kerala, India, a stipitate Ganoderma species with a distinctly laccate pileus was collected from the dead stump of Artocarpus hirsutus (Lam.).Detailed morphological examination revealed taxonomically important features including a trimitic hyphal system, ellipsoid double-walled basidiospores with interwall pillars, and a hymeniodermic pileus crust, which are consistent with the diagnostic characteristics of G. tropicum.To support species identification and confirm phylogenetic placement, the Internal Transcribed Spacer (nrITS) region of rDNA was amplified, sequenced, and compared with reference sequences retrieved from GenBank.Phylogenetic analysis using the Maximum Likelihood (ML) method revealed that the Kerala material nested within a strongly supported clade (97% bootstrap) comprising sequences of G. tropicum from China, India, Taiwan, and Thailand.This integrative approach confirms the taxonomic identity of the specimen as G. tropicum, marking its first record from Thiruvananthapuram District and the first known occurrence on the endemic host Artocarpus hirsutus.This study contributes valuable data on the geographic distribution, host range, and genetic relationships of G. tropicum, and emphasizes the importance of coupling classical taxonomy with molecular tools for resolving species boundaries and uncovering fungal diversity in tropical regions.