7 Anatomical Study of the Leaves and Roots of Subtribe Coelogyninae Benth., Tribe Coelogyneae Pfitzer G. Dangol 1 , S. Rajbhandary 1 and D. M. Bajracharya 2 1 Central Department of Botany, Tribhuvan University, Kirtipur 2 Department of Botany, Amrit Campus, Tribhuvan University, Lainchour, Kathmandu E-mail: dangol_gita@hotmail.com Abstract Anatomical structures of the leaves and roots of five genera of subtribe Coelogyninae were studied and their taxonomic significance and relationship were identified. Some variations among the genera and species are elicited. Key words: Orchid, Stomata, Taxonomy Introduction The Subtribe Coelogyninae (Orchidaceae) comprises 20 genera and 285 species (Dressler 1993), distributed throughout the world in tropical, subtropical and temperate regions. In Nepal, they are distributed in eastern and central regions, altitude ranging from 450m to 3600m. Among them Pleione coronaria has been reported as an endemic species of Nepal recorded from Ganesh Himal. Only few studies have been done on the epidermal and stomatal aspects of Coelogyninae. Rao and Khasim (1987) analyzed the evolutionary trends in Orchidaceae on the basis of growth habit and vegetative anatomy of 43 species of Indian orchids and reported cyclocytic stomata in the subtribe Coelogyninae. The evolution of stomatal types has progressed from anomocytic to diacytic to cyclocytic to paracytic. It was concluded that the epiphytic habit has evolved from the terrestrial one and the monopodial growth in the epiphytes is derived from sympodial habit. Singh and Singh (1974) studied the organization of stomatal complex in some Orchidaceae including some species of Coelogyne and Pholidota in which the presence of tetracytic stomata were considered significant in evolutionary relationships of the family. Kaushik (1983) gave a detailed ecological and anatomical marvel of the Himalayan Orchids and proposed a new classification for Orchidaceae on the basis of the anatomical findings. Mohana Rao et al. (1988) studied the vegetative anatomy of Panisea uniflora and observed the differences in several characters from the species of Coelogyne. Mohana Rao et al. (1991) studied the vegetative anatomy of some species of subfamily Epidendroideae and found the differences among the species with respect to stomatal features and presence or absence of trichomes, cellulose thickened mesophyll cells and fibrous bodies. The comparative analysis of the anatomical features indicated the close relationship between Bulbophyllum fischeri and Coelogyne odoratissima. In the present study, we have included five illustrations (Fig.1) out of six genera found in Nepal. Altogether 20 species have been investigated for the analysis of vegetative anatomical features. This study holds an objective to provide information on the anatomical characteristics of the subtribe Coelogyninae of Nepal. Since, the study of anatomical features of Orchid species have not rather been done in Nepal, this study will provide data for a later comprehensive analysis of anatomical characteristics on these taxa. Materials and Methods Plant materials for anatomical and stomatal studies were collected from TUCH, KATH, and Amrit Campus, Lainchour. The anatomical study of stem and leaf was also done to see if these characters are taxonomically significant. For anatomical study, the dried materials were pre-treated. The materials under the study were soaked in 9:1 solution of water and glycerol for 24 hours to make it soft and easy to cut the section. In case of hard material the time of treatment was extended for several hours. After the treatment the plant parts were sectioned for anatomical studies. The transverse section of stem was prepared for the study of stem anatomy. Fine sections were dehydrated with different alcohol series i.e. 30% for 15 minutes, 50 % for 15 minutes, 70 % for 15 minutes, 90 % and finally absolute alcohol for 10 minutes. At the time of dehydration staining was done by using safranin and light green for preparation of permanent slides. After the treatment the material was transferred in to the slide then mounted by DPX.