Record of Oldenlandia hygrophila Bremek . ( Spermacoceae : Rubiaceae ) , a lesser known herb from Palghat Gap of Western Ghats , Kerala , India

For Focus, Scope, Aims, Policies, and Guidelines visit https://threatenedtaxa.org/index.php/JoTT/about/editorialPolicies#custom-0 For Article Submission Guidelines, visit https://threatenedtaxa.org/index.php/JoTT/about/submissions#onlineSubmissions For Policies against Scientific Misconduct, visit https://threatenedtaxa.org/index.php/JoTT/about/editorialPolicies#custom-2 For reprints, contact <ravi@threatenedtaxa.org> Note


Journal of Threatened
of the family Rubiaceae is well distributed in the tropical and subtropical regions of the world (Govaerts et al. 2013). In India, the occurrence of the genus Oldenlandia is often debated with variable number of citations as 27 species (Hooker 1880) in the Flora of British India and 45 species (Gamble & Fischer 1923) in the Madras Presidency region alone. Estimates reveal the documentation of 14 species and one variety from the state of Kerala (Sasidharan 2011;Jose et al. 2015;Soumya et al. 2017).

Materials and Methods
During the exploratory studies on the floristic diversity of granitic hillocks in Walayar forest range of southern Western Ghats, the authors came across this taxon growing on the rocky outcrops near the dam site of Malampuzha in Palakkad District in July 2017. The specimens of the taxon were procured and herbarium was prepared using standard herbarium procedures. The plant specimens were characterised, measured and illustrated.
The specimen was identified to be Oldenlandia hygrophila Bremek. collected by Prof. Vasudevan Nair in 1972 cited from Malampuzha dam vicinity of Palakkad District (Bremekamp 1974) and confirmed the taxa from the type specimens deposited at Kew Herbarium (O. hygrophila: bar code no: K000031277). Regional herbaria (MH, KFRI and CALI) were consulted to check the presence of earlier collections of the taxon and found that N. Sasidharan had collected the taxa from Thrissur District in 1987 (Acc. No. KFRI 6945, collection No: N.S. 4635). Later, the taxa was reported from Muthanga region of Wayanad District in Kerala by Ratheesh Narayanan (RNMK 2228) in 2009. The taxon J TT was not able to relocate from its type locality after its first collection by Prof. R. Vasudevan Nair in 1972. The acronyms for the herbaria follow the Index Herbariorum (Thiers 2018). The protologues of the allied taxa Oldenlandia pumila (L.f.) DC. and Oldenlandia dineshii Sojan & V. Suresh were also compared. Bremek., Kew Bull. 29: 359. 1974;Narayanan, Fl. Stud. Wayanad Dist. 435. 2009.
Annual, erect, branched or unbranched herbs, 25-130 mm tall. Entire plant with sparsely distributed setiform cuticular protuberances. Stem quadrangular, minutely winged when old. Stipules connate, interpetiolar, 1.5-2     Collection no: N.S. 4635, 22.ix.1987, Peechi, Thrissur, coll. N. Sasidharan. Ecology: This plant grows at an elevation of 14-252m in hydro geomorphic exposed rock surfaces along with Drosera indica L., Utricularia lazulina P.Taylor, U. graminifolia Vahl, Indigofera uniflora Buch. -Ham. Palghat gap region covering the nearby forest ranges also could not locate the taxon. This gives us evidence of its narrow distributional range and that it can considered endemic to southern Western Ghats (restricted to Kerala). Till date, the taxon's existence was doubted due to lack of collection or further reports. This may be the reason that the taxon has not yet been evaluated as per the IUCN Red List 2019. Since the population size is very small, distributed in a narrow stretch of hydrogeomorphic habitats of less than 10km 2 , the taxon can be assigned the status of Critically Endangered (CR) as per IUCN version 2019-3 (IUCN 2019).

Taxonomic delineation of Oldenlandia hygrophila from O. dineshii and O. pumila
Oldenlandia hygrophila is similar to O. dineshii in quadrangular stem and possession of blue flowers, but differs in the presence of setiform cuticular protuberance all over the plant, solitary axillary flowers smaller in size (2.5-3.0 x 1.5-2.0 mm), corolla lobes not spreading when open, sepals reaching one fourth the length of corolla tube, corolla tube glabrous outside, but with hyaline hairs at the base inside and glabrous staminal filaments. O. hygrophila differs from O. pumila in having erect nature of plant, linear-lanceolate leaves, solitary axillary blue flowers, shorter pedicels, calyx lobes reaching one-fourth the level of corolla lobes, corolla with minute hyaline hairs at the base of corolla tube inside and with sub-globose capsule. Comparison of taxonomic characters of O. hygrophila with O. dineshii and O. pumila is given in Table 1.