Peristylus sahanii, a new species of Orchidaceae from India Pankaj Kumar 1 , Gopal Singh Rawat 1 & Jeewan Singh Jalal 1 Summary. Peristylus sahanii (Orchidaceae), a new species from Jharkhand state (Chotanagpur plateau), India is described and illustrated. Key Words. Chotanagpur, new species, Orchidaceae, taxonomy. Introduction The genus Peristylus Blume is represented by 106 species and three varieties, of which 29 species and two varieties are found in India (Misra 2007). It is distributed from the Mascarenes, tropical and sub- tropical Asia to the Pacific region (Govaerts et al. 2008). The identification of species within the genus is difficult due to poorly defined contrasting characters with allied genera such as Habenaria Willd. and Pecteilis Raf. The genus can be differentiated from its allies by the ascending ovary, close and parallel to the peduncle and stigmatic surfaces in the form of small protuberances on the edge of the lip and not extending as stalked appendages as in Habenaria. While conducting an orchid survey in the state of Jharkhand as a part of the AICOPTAX project funded by Ministry of Environment and Forests, Government of India, a species of Peristylus Blume was collected. This species was found to be distinct from an allied species, i.e. Peristylus stocksii Kraenzl. A similar species was collected by Haines (1924) but he hesitantly included it under P. stocksii although he did point out some distinctions in morphological characters. The present work deals with the description of the same as a new species from Chotanagpur (Jharkhand), India. The state of Jharkhand was previously repre- sented by four species (Kumar et al. 2007). The present report makes it five species from the state and 30 species from India. A key for the identification of the five species from Chotanagpur is provided. Peristylus sahanii P. Kumar, G. S. Rawat & J. S. Jalal sp. nov. affinis P. stocksii sed tubero subgloboso, inflorescentia subsecunda, floribus flavo-virentibus, bracteis floralium ovario brevioribus, labello sepalis longiore satis differt. Typus: India, Jharkhand, Latehar, Netarhat vallis, 450 m alt., 8 Aug. 2005, Pankaj Kumar 051039 (holotypus WII!). http://www.ipni.org/urn:lsid:ipni.org:names:77104379-1 Herbaceous, terrestrial, unbranched, erect up to 35 cm tall. Tubers 1 (- 2) (second tuber present, if the previous year’s tuber persists), subglobose, 1.7 × 1.2 cm. Roots many, vermiform, 0.1 cm thick, cylin- dric. Stem up to 20 × 0.3 cm. Leaves clear green, scattered towards the lower half of the plant, unequal, tapering towards the base, upper ones ovate, 8.5 × 2.5 cm, lower ones obovate, 8.5 × 3 cm. Leaf apex acute, margins undulate, leaf base sheathing the stem, veins 3. Inflorescence erect, up to 25 cm long, many- flowered. Flowers subsecund densely placed towards terminal end. Peduncle up to 15 cm long, terete, with 2 sterile amplexicaule bracts, up to 1.6 cm long. Pedicel with ovary 0.7 cm long, 0.13 cm thick. Flower pale yellowish-green, odourless. Floral bracts ovate, acute to slightly acuminate, 0.8 × 0.3 cm, pale green, shorter than ovary. Dorsal sepal, pale green, ovate- elliptic, margin entire, 0.2 × 0.15 cm. Lateral sepal oblong-ovate, oblique, 0.25 × 0.15 cm. Petals obliquely ovate-elliptic, 0.25 × 0.2 cm. Lip 0.43 × 0.35 cm, pale green, 3-lobed, succulent, continuous with column, small transverse callus near the base. Base 0.18 cm broad. Mid-lobe green, obtuse-oblong, 0.25 × 0.13 cm. Side lobes thinner and shorter than mid lobe, elliptic- oblique, 0.2 × 0.07 cm. Spur slightly shorter than ovary, 0.5 cm long, elongated, clavate with longitudinal ridge towards the lower swollen end. Column 0.1 cm long, globular. Stigmatic lobes clavate, connate to the walls of hypochile along with staminodes, not protruding outside. Ovary 0.7 cm long, sessile, close to rachis, ridged. Anther locules tending to converge at both ends, obpyriform, antherophores absent. Pollinia pyriform, caudicles very short or absent, viscidium ovoid. Figs 1 and 2. DISTRIBUTION. Netarhat Valley, Latehar Distr., Chota- nagpur, Jharkhand, India. SPECIMEN EXAMINED. INDIA. Jharkhand: Latehar, Netarhat, 8 Aug. 2005, Pankaj Kumar 051039 (holotype WII!). HABITAT. On shady (85% canopy cover) hill slopes of a Shorea robusta Roth (Dipterocarpaceae) dominated Accepted for publication March 2010. 1 Habitat Ecology Department, Wildlife Institute of India, Post box # 18, Dehradun, 248001, Uttarakhand, India. e-mail: pankajsahani@rediffmail.com KEW BULLETIN VOL. (65):1 – 4 (2010) © The Board of Trustees of the Royal Botanic Gardens, Kew, 2010