Phytolith Morphotype Composition in Some Members of Zingiberales From Eastern Himalayas and Their Taxonomic Significance

Phytoliths are microscopic silica particles that aid taxonomic differentiation and reconstruction of vegetation and climate in both modern and past contexts. Members of the order Zingiberales constitute important components of tropical and subtropical vegetation, yet their phytolith diversity remains poorly documented, particularly in the eastern Himalayas. The present study investigates phytolith morphotype diversity and silica accumulation patterns and the taxonomic significance of phytolith assemblages in six eastern Himalayan Zingiberales representing the families, Cannaceae ( Canna indica ), Costaceae ( Cheilocostus speciosus ), Heliconiaceae ( Heliconia rostrata ), Marantaceae ( Phrynium pubinerve ), Musaceae ( Musa balbisiana ), and Zingiberaceae ( Elettaria cardamomum ). Dry weight–acid‐insoluble fraction (AIF) analysis, supported by Kruskal–Wallis test, reveals significant interspecific variation in silica accumulation among the investigated taxa. Among the fifteen identified morphotypes, nine (EPIDERMAL CAVATE FLAT, EPIDERMAL CAVATE SHALLOW 1, EPIDERMAL CAVATE SHALLOW 2, AMEBOID, EPIDERMAL IRREGULAR SINUATE, CONICAL VERRUCATE, SPHEROID PLICATE RIDGED 1, SPHEROID PLICATE RIDGED 2, and SPHEROID PLICATE) exhibit diagnostic potential for distinguishing the investigated taxa. Morphometric analysis based on 17 size‐ and shape‐related parameters, supported by Multivariate Analysis of Variance (MANOVA), demonstrate significant differences among phytolith morphotypes. Cluster Analysis and Principal Component analyses (PCA) further reveal distinct phytolith assemblage patterns and taxon‐specific associations, supporting the taxonomic significance of the recovered morphotypes. An artificial identification key based on phytolith characters is proposed for the investigated taxa. Several morphotypes demonstrate potential ecological significance as indicators of tropical to subtropical eastern Himalayan vegetation. These findings highlight the taxonomic significance of phytolith assemblages in eastern Himalayan Zingiberales and provide a valuable modern reference framework for vegetation reconstruction and archaeobotanical investigations.