Comprehensive knowledge of plant anatomy is an absolute necessity for accurately identifying taxa during their vegetative phase. Orchidaceae family has been extensively studied in the Himalayan region, with a focus on morphology and floristics. However, the anatomy of orchid roots has not been investigated in detail. This study examines the root anatomy of six Himalayan Dendrobium species (D. chrysanthum, D. densiflorum, D. longicornu, D. nobile, D. rotundatum, and D. transparens) using standard plant anatomy techniques. Qualitative and quantitative traits were observed and analysed, including the multi-layered velamen, stele and cortical tissue area, and number of xylem strands, which are distinct characteristics of genus Dendrobium. ANOVA and Tukey's test at 5% significance level were used to quantitatively examine cross-sections of the roots and identify significant differences. All six studied taxa possess velamen tissues with cells having spirally thickened walls, and a single-layered exodermis with cells of varying sizes. The cortex was multi-layered and contained parenchymatous water-storage cells, while a uniseriate endodermis with passage cells were observed. D. chrysanthum and D. rotundatum had xylem and phloem elements embedded in parenchymatous tissues, whereas D. densiflorum, D. longicornu, D. nobile, and D. transparens had xylem and phloem elements embedded in sclerenchymatous tissues. Cell sizes in different root tissues varied significantly. A dichotomous key based on the root anatomical traits for the identification of these Dendrobium species is provided. Future research is suggested to explore additional parameters and to conduct experiments to understand its anatomical response to epiphytism.

全面的植物解剖学知识对于准确识别植物生长阶段的分类群是绝对必要的。兰科在喜马拉雅地区得到了广泛的研究，重点是形态和植物区系。然而，兰花根的解剖结构尚未得到详细研究。本研究使用标准植物解剖学技术检查了六种喜马拉雅石斛兰（D. chrysanthum、D. densiflorum、D. longicornu、D. nobile、D. rotundatum和D. transparens）的根部解剖结构。对石斛属植物的质性和数量性状进行了观察和分析，包括多层质皮、中柱和皮层组织面积、木质部束数等。使用方差分析和 5% 显着性水平的 Tukey 检验来定量检查根的横截面并识别显着差异。所有六个研究的类群都拥有含有螺旋增厚细胞壁的表皮组织和含有不同大小细胞的单层外皮。皮层是多层的，含有薄壁组织的储水细胞，同时观察到具有传代细胞的单列内皮层。D. chrysanthum和D. rotundatum的木质部和韧皮部成分嵌入薄壁组织中，而D. densiflorum、D. longicornu、D. nobile和D. transparens 的木质部和韧皮部成分嵌入厚壁组织中。不同根组织的细胞大小差异很大。提供了基于根解剖特征的二分键，用于识别这些石斛兰物种。建议未来的研究探索其他参数并进行实验以了解其对附生现象的解剖学反应。