In this study, karyomorphological studies of five lithophytic species of the genus Dendrobium Sw. from Manipur (Orchidaceae) were made. These were viz., Dendrobium aphyllum (Roxb.) C.E.C. Fisch., D. crepidatum Lindl., D. devonianum Paxt., D. fimbriatum Hook. and D. nobile Lindl. Chromosome counts of those five lithophytic species were studied for the first time from Manipur, India. Dendrobium shows the basic chromosomes number X = 19 and 20. The five species studied were diploid (2n) with chromosome number 2n = 40 in three species (D. aphyllum, D. fimbriatum and D. nobile) and 2n = 38 in remaining two species (D. crepidatum and D. devonianum). The highest Total Chromosome Length (TCL) and Mean Chromosome Length (MCL) were observed in D. fimbriatum (59.45 μm and 4.07 μm respectively), while D. nobile had lowest TCL (53.50 μm) and MCL (3.25 μm). Chromosomes were mostly median to sub-median in all studied taxa, however, median chromosomes were more dominant. No polyploids were observed. Categorization as per Stebbins’ classification were done for all the species; the karyotype asymmetry of D. crepidatum and D. fimbriatum were in 3A category while the remaining three species viz., D. aphyllum, D. devonianum and D. nobile were in 3B category. The present study will help in establishing taxonomic and ecological relationships between lithophytic species of the genus based upon cytology.

在本研究中，对石斛属Sw属的 5 种岩生植物进行了核形态学研究。从曼尼普尔邦（兰科）制成。它们是Dendrobium aphyllum (Roxb.) CEC Fisch.、D. crepidatum Lindl.、D. devonianum Paxt.、D. fimbriatum Hook。和D. nobile Lindl。印度曼尼普尔邦首次研究了这五种岩生植物的染色体计数。石斛显示基本染色体数 X = 19 和 20。研究的五个物种是二倍体 (2n)，在三个物种（ D. aphyllum，D. fimbriatum和D. nobile）中染色体数 2n = 40) 和 2n = 38 在其余两个物种 ( D. crepidatum和D. devonianum ) 中。在D. fimbriatum中观察到最高的总染色体长度 (TCL) 和平均染色体长度 (MCL)（分别为 59.45 μm 和 4.07 μm），而D. nobile的 TCL (53.50 μm) 和 MCL (3.25 μm) 最低。在所有研究的分类群中，染色体大多位于中位至亚中位，然而，中位染色体更为显性。没有观察到多倍体。根据 Stebbins 的分类对所有物种进行分类；D. crepidatum和D. fimbriatum的核型不对称性属于 3A 类，而其余三个物种即D. aphyllum和D. devonianum和D. nobile属于 3B 类。本研究将有助于基于细胞学建立该属岩石植物物种之间的分类学和生态学关系。