Orchidaceae is one of the most highly evolved and fascinating families among angiosperms. It’s unique floral structure not only attracts pollinators, but also captivated human interest for centuries. Additionally, orchids possess significant medicinal properties that have been recognized since the Vedic era. The Rarh region of West Bengal, India is distinct for its unique physio geographical characteristics and diverse tribal communities. Due to their specialized floral structures, it becomes an important and most precious ornamental group of plants. Orchids contribute significantly to biodiversity and also used in traditional medicinal practices. Present study represents on the documentation of orchid diversity in the region with reference to its ecological significance through field survey and collected the informations regarding their medicinal applications, highlighting the need for conservation efforts.

Enumeration, Medicinal, Orchidaceae, Rarh-Bengal, West Bengal.

Orchids are incredibly diverse and alluring plants, found in abundance in nearly every region worldwide except polar and arid desert environments (Pant, 2013; De & Singh, 2015; De et al., 2015; Zhang et al., 2018). The name Orkhis was first introduced by Theophrastus around 300 B.C., while the term Orchidaceae was coined by Carl Linnaeus in the year 1737 and later formally established by Antoine Laurent de Jussieu in the year 1789 (Anghelescu et al., 2020; Dressler, 1993; Hegde, 2005). In India, orchids have been recognized since the Vedic period, with Vanda tessellata and Flickingeria macraei mentioned in the Rigveda and Atharvaveda for their medicinal properties (Ninawe & Swapna, 2017). The family Orchidaceae is one of the most widespread and ecologically significant group of flowering plants. It is the second-largest family within Liliopsida, encompassing ca. 25,000-35,000 species across under 900 genera worldwide (Cribb et al., 2003), contributing about 8% of angiosperm diversity. Out of six perianths of the flower, outer three sepaloid and inner three petaloid, one of which is modified into a specialized structure called the labellum. Another distinctive feature of this family is the presence of Gynostemium, which is the Pollinia bearing unique central column of a flower formed by the fusion of androecium and gynoecium. Pollinia is actually the modified anther. Orchids are highly valued not only for their intricate and striking flowers but also for their extensive use in traditional medicine (Handa, 1986). However, the effects of climate change and overharvesting for ornamental and therapeutic purposes have placed many species at risk. As of 2017, the IUCN Global Red List included 948 orchid species, with 56.5% classified as threatened (De, 2020). 

Orchidaceae is the largest family of higher plants in India, with its distribution primarily concentrated in the Eastern and Northeastern Himalayas, the Northwestern Himalayas, Peninsular India, and the Andaman and Nicobar Islands (De, 2020). India is home to approximately 1,300 orchid species belonging to 140 genera (Bhunia et al., 2021), representing about 5.98% of the global orchid flora and 6.83% of India's total angiosperm diversity (De, 2020). Orchids in West Bengal are primarily concentrated in North Bengal, though a few species are also found in the southern region (Mitra et al., 2020). Within South Bengal, the Rarh region stands out as a significant center of orchid diversity. Orchids in this region exhibit both epiphytic and terrestrial growth habits, with commonly found species including Vanda tessellata and Dendrobium aphyllum. Epiphytic orchids are primarily found growing on the trunks of Shorea robusta and Diospyros melanoxylon, whereas terrestrial orchids thrive in the shaded understory of evergreen forests or grasslands. Beyond their ecological and economic significance, orchids play a crucial role in both biodiversity and traditional medicinal practices. Though fragmentary district wise new reporting and floristic works of this region have been published previously (Mandal & Nandi 2012; Karmakar & Rahaman, 2022; Mandal et al., 2022; Paul & Pati, 2023), but still now there is no comprehensive cumulative work on orchid diversity along with their distribution and medicinal uses have not been published yet. This research documents the region's orchid diversity through field surveys and explores their medicinal uses, emphasizing the importance of conservation efforts.

STUDY AREA: Rarh region of West Bengal is well known for its physio-geographical characters, which lies between the latitude of 21 39′43″ N to 24 35′51″ N and longitude of 85 49′27″ E to 88 28′43″ E. This region is surrounded by the 'Ganges delta' to the East and the 'Choto-Nagpur plateau' to the West. It covers 6 districts of West Bengal (Fig. 1) viz. Bankura, Birbhum, Jhargram, Paschim Bardhaman, Paschim Medinipur, and Purulia. The Chota Nagpur Plateau in West Bengal includes parts of Purulia, Bankura, and Paschim Medinipur, acting as a transition zone to the Gangetic Plain. It features a rugged, forested landscape with hills and valleys, and is one of India's least explored biogeographic regions. Covering about 120,000 km², it consists of ancient Precambrian rocks and Gondwana formations. Geologically, it is part of the Deccan Plate, which collided with Eurasia millions of years ago (Haines, 1910; Kumar et al., 2007). 

Extensive field surveys were conducted successfully from October, 2022 to March, 2024 for the documentation of the orchid flora through random collection across various vegetation types in the selected study areas at different seasons. A significant challenge was locating specimens in their reproductive stage (flowering only) due to the diverse flowering seasons and distribution patterns of each species. Fresh specimens were collected from different locations, placed in zipper bags, and transported to the laboratory for identification and herbarium preparation. During field trip the ecological details, including natural habitat, host plants, and flowering and fruiting periods, were recorded. Field images of the specimens were captured using Nikon D3400 and D7000 cameras. In the laboratory, the collected specimens were identified by consulting the available literature (Malick, 1977; Hooker, 1890; Haines, 1910 & 1924; Prain, 1903; Sanyal, 1994; Panda & Das, 2004; Kumar et al., 2007), and species nomenclature was verified using authoritative online databases such as Plants of the World Online (https://powo.science.kew.org) and the International Plant Names Index (https://www.ipni.org). Herbarium specimens were prepared using the standard herbarium method (Jain & Rao, 1976) and deposited at the Uluberia Botanical Institute Herbarium (UBIH). After successful identification, reviewing the medicinal properties of these orchids.

In the present study the authors reported 29 species of Orchidaceae under 16 genera along with their common name, flowering, fruiting time, and habitat of Rarh-Bengal region in West Bengal (Table. 1). Among them, 12 species are epiphytic and 17 species are terrestrial in nature (Fig. 2). Most frequently distributed genus in the concerned region is Eulophia which represents six species viz., E. diffusiflora, E. explanata, E. graminea, E. nuda, E. ochreata, and E. picta, followed by the genus Habenaria (representing five species viz. H. commelinifolia, H. digitata, H. marginata, H. plantaginea, and H. reniformis); Aerides; Dendrobium; Nervilia; Vanda; Acampe; Cymbidium; Didymoplexis; Luisia; Oberonia; Pelatantheria; Peristylus; Rhynchostylis; Tropidia, and Zeuxine (Fig. 3). Throughout the survey, it was observed that the diversity of orchids was rich in Ajodhya hills of the district Purulia. Medicinal value of the Rarh-Bengal orchids has also been represented in Table 2, whereas the useful parts of different Rarh-Bengal orchids used for treatment has been represented in Fig. 4. The diseases related to Sexual disorders are the Maximum treated in the Rarh region of Bengal by the orchid (Fig. 5).  

The presence of Gondwana substrates, the Deccan Plateau, and ancient Precambrian rocks contributes to the unique floristic composition of this region. The plateaus of Northeast India, along with the Western Ghats and Eastern Himalayas, are recognized as orchid biodiversity hotspots, with the Chota Nagpur Plateau serving as a biogeographic junction (Kumar et al., 2007; Kumar & Rawat, 2008). In the Jharkhand portion of Chota Nagpur, 64 orchid species have been recorded, five of which are endemic to the region (Kumar & Rawat, 2008). The present study documents 29 orchid species from the Rarh region, representing a significant addition to the existing knowledge contributed by earlier works on local orchid flora. Previous studies by Manoranjan et al. (2020); Chakraborti et al. (2021); Islam et al. (2023) reported 14, 27, and 18 species, respectively from this area. Consistent with the findings of Manoranjan et al. (2020), several species—Acampe praemorsa, Aerides multiflora, Aerides odorata, Dendrobium macrostachyum, Luisia tristis, Peristylus constrictus, and Rhynchostylis retusa —were found to be restricted to hilly terrains. Zeuxine strateumatica was observed only in grasslands near the foothills, such as those in Bandwan. Additionally, Cymbidium aloifolium, Dendrobium macrostachyum, Didymoplexis pallens, Eulophia explanata, E. graminea, E. nuda, E. ochreata, E. picta, certain species of Habenaria, and Pelatantheria insectifera are primarily confined to hill regions and exhibit limited distribution within this area. In contrast, species like Vanda tessellata, Tropidia curculigoides, Dendrobium aphyllum, and Oberonia falconeri were found to be very common and widely distributed throughout the area.

Due to their significant medicinal value and ornamental appeal, many orchid species are frequently harvested by local communities for traditional medicine and home decoration. The Rarh region is also well known as a "fire forest" because of its dominance by vibrant species such as Butea superba, Butea monosperma, Bombax ceiba, and Erythrina variegata. However, biodiversity in this region has been severely impacted by development projects, such as the construction of a dam in the Ajodhya Hills. At the same time, the region's natural beauty has led to a steady rise in tourism, with locations like the Ajodhya Hills and its adjoining areas, Garh Panchakot Hills, Baghmundi, and Susunia Hills experiencing rapid development. This expansion, driven by agriculture and illegal construction, has become a major cause of deforestation. Furthermore, invasive plant species such as Parthenium hysterophorus, Lantana camara, Mikania micrantha, Eucalyptus hybrids, and Acacia auriculiformis are contributing to habitat degradation, significantly threatening native flora, including orchids. These factors combined are leading to a steady loss of orchid habitats. On the other hand, climatic change also affects the natural habitat of orchids.

This is a critical time to prioritize the conservation of existing orchid species in the region. According to the IUCN (2021), conservation refers to the protection, care, management, and maintenance of ecosystems, habitats, wildlife species, and populations, whether within or outside their natural environments, to ensure their long-term survival. In India, several initiatives have been undertaken to conserve rare, endangered, and threatened orchids by organizations such as the Botanical Survey of India, State Forest Departments, the Indian Council of Agricultural Research, and other governmental bodies. Similarly, conservation strategies include the establishment of orchidarium, orchid trails, and orchid reserves across different parts of this region have to be implemented. 

Fig. 1. The Study area Rarh-Bengal.

Fig. 2. Habitat distribution of orchids.

Fig. 3. Species distribution for genera.

Fig. 4. Uses of Plant part.

Fig. 5. Plant vs. Disease treated.

Table 1: Diversity of Orchid species in Rarh-Bengal.

Table 2: Documentation on  Medicinal uses of Orchids.

Due to its unique geographical position, divers’ climatic conditions, and edaphic factors, the rarh region provides a platform for growing different floral and faunal wealth. Present communication recorded 29 orchid species, which are fully used as medicinally important plants in traditional systems, except one (Didymoplexis pallens). They are being used more by people, which is causing their number depletion & putting them at risk of disappearing from the wild. Due to anthropogenic activities and over-exploitation of orchids, conservation aspects are essential to preserve their biodiversity and ensure the survival of these interesting plants in the scenario of habitat loss and climate change.

Significant gaps remain in our understanding of orchid populations, including their spatial distribution, climatic niches, the impacts of climate change on their survival, the severity of various threats, market dynamics, and species-specific conservation and management strategies in the selected areas. Additional knowledge gaps include limited information on the available stock of orchid species, cultivation and harvesting practices, end users and intermediaries, and the quantities of raw materials traded within the state.