A new species of Dillenia (Angiosperms: Dilleniaceae) from the Eastern Ghats of Andhra Pradesh, India

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The genus Dillenia L. is represented by ca. 60 species distributed from Madagascar and Seychelles to the Fiji Islands and India to southeastern Asia and Australia (Hoogland 1952;Mabberley 2008). In India the genus is represented by seven species (Majumdar 1993), of which four are reported from Andhra Pradesh (Pullaiah et al. 2018). Dillenia andamanica C.E. Parkinson and D. bracteata Wight are strictly endemic to the Andaman & Nicobar Islands and the Western Ghats, respectively (Singh et al. 2015). Initially, D. bracteata Wight was also reported from Sri Lanka based on Wight collections, but, while revising the family, Wadhwa (1996) ruled out the distribution in Sri Lanka and stated that 'both specimens are wrongly labelled'.
While working on the project 'Non Detrimental Finding Studies (NDFs) on Red Sanders (Pterocarpus santalinus L.f.) tree in India', a Dillenia species with white flowers was collected from the Chittoor District of Eastern Ghats, Andhra Pradesh. After critical studies and comparison with all known species, the material is recognized as a novelty that markedly differs from all known species of Dillenia. Hence, it is described here as a new species. Diagnosis: Dillenia tirupatiensis is allied to D. hookeri by its inflorescence, bracteoles, and shape of seeds but differs by its elliptic-obovate leaves (oblongoblanceolate in D. hookeri), crenate margins (entire to slightly dentate in D. hookeri), 8-10 mm long pedicel (15-40 mm in D. hookeri), 8mm long bracteoles (20-35 mm in D. hookeri), white flowers (yellow in D. hookeri), ovules that are in four rows at the base and two rows at the apex of the placenta (two rows in D. hookeri) and styles that are erect and parallel for up to 3mm before spreading (spreading from the base in D. hookeri) ( Table  1).
Etymology: The specific epithet is derived from the type locality Tirupati, a famous temple town in the Chittoor district of Andhra Pradesh.
Conservation status: This species is so far known only from the type locality and a total of five mature individuals in the surrounding areas. Extensive explorations, however, are needed in nearby locations and similar habitats to know the exact extent of occurrence of this species, for an accurate evaluation of its threat status. Therefore, the threat status is provisionally evaluated here as "Data Deficient (DD)" using the IUCN Red List Categories and Criteria Version 3.1 (IUCN 2012).
Notes: Dillenia bracteata is related to D. tirupatiensis by its leaf shape and size, equal stamens and arrangement of styles but differs by having 0-2 small bracteoles, 2-6-flowered racemes, yellow flowers, and ovules arranged in 2 rows in the carpels. Dillenia retusa reported from Karnataka, Tamil Nadu, and Sri Lanka, is also similar to the new species by its inflorescence, and flower colour but differs by its fewer lateral nerves in the leaves, ebracteolate flowers, unequal stamens, and styles spreading from the base.