Ta iwa nia 60(2): 95‒98, 2015 DOI: 10.6165/tai.2015.60.95 NOTE Ixora longibracteata Bremek. (Rubiaceae), An Addition to Flora of India, with Notes on its Status and Distribution Kaliyamurthy Karthigeyan(1*) and Wilson Arisdason(2) 1. Central National Herbarium, Botanical Survey of India, Howrah – 711 103, West Bengal, India. 2. Botanical Survey of India, CGO Complex, Salt Lake City, Kolkata – 700 064, West Bengal, India. * Corresponding author: karthigeyan.murthy@gmail.com (Manuscript received 15 July 2014; accepted 31 March 2015) ABSTRACT: Ixora longibracteata has been rediscovered after its type collection from Jaldapara National Park, West Bengal, India, earlier known only from its type locality, Chittagong hill tracts in Bangladesh. This species is also reported here as an addition to the flora of India. Besides, hitherto undescribed morphology of fruit of this species is provided here in the description for the first time with photograph. A detailed description, illustration, photograph, distribution map and conservation status of the species are provided here to facilitate its easy identification. KEY WORDS: Bremekamp, Ixora, New Record, Rediscovery, Rubiaceae. INTRODUCTION Ixora L., the third largest genus of the family Rubiaceae, is distributed in tropical and subtropical regions of the world, and represented by ca. 500 species (Mouly et al., 2009). Though the genus is pantropical in distribution, its greatest species density is found in the Malaysian Archipelago with its maximum in Borneo (Bremekamp, 1937a). Ixora is characterised by its terminal inflorescence with tetramerous flowers. It differs from its very closely allied genus Pavetta, by the exserted part of the style being as long as the corolla lobes, sometimes even much shorter, and the two stigmatic lobes separate (divaricate) entirely. Linnaeus (1753) established the genus, Ixora with two species, namely Ixora coccinea and Ixora alba. Hooker (1880) recorded 37 species and 5 varieties, besides 4 imperfectly known, doubtful, and rejected species from the then flora of British India. Bremekamp (1937a, b and 1938) and Corner (1941) made a comprehensive study on the species of Ixora, confined to Indo-Burmese and Malesian regions, respectively. Bremekamp (1959) described five new species, namely Ixora longibracteata and Ixora tigriomustax, from Chittagong hill tracts, Ixora athroantha, from Sukna, West Bengal, Ixora rangonensis, from Myanmar and Ixora tenuifolia, from Great Nicobar. According to Santapau and Henry (1973) there are ca. 30 species of Ixora in India. Husain and Paul (1989), who have made a comprehensive taxonomic study on the Indian species of Ixora, reported 42 species, 5 varieties and 6 forms under 2 subgenera and 6 sections from the present political boundary of the country. Apart, during the early and late 1990s a few novelties, viz. Ixora agasthyamalayana Sivad. & N. Mohanan (Sivadasan and Mohanan, 1991) and Ixora sivarajiana Pradeep (Pradeep, 1997) were described from Western Ghats of Kerala in southern India, and Ixora kachinensis from northeastern India and Ixora pseudoacuminata from Myanmar were described by Deb and Rout (1992). Recently, I. rangonensis Bremek., a species earlier considered as an endemic to Rangoon district of Myanmar was also reported as an addition to India from Kalain Range of Borail Wildlife Sanctuary in the Cachar district of Assam by Barbhuiya (2012). The Jaldapara National Park (25°58ꞌ–27°45ꞌ N and ° 89 08ꞌ–89°55ꞌ E) is situated on the banks of Torsa River in Jalpaiguri district of West Bengal state, covering an area of 216.5 km2. It was established in 1941 as Jaldapara Wildlife Sanctuary, to conserve the Great Indian One-horned Rhinoceros, which was later declared as a National Park in May 2012 (Ghosh et al., 2013). Banerjee (1993), who explored the plant resources of Jaldapara National Park, recorded only two species of Ixora, namely Ixora arborea Roxb. ex Sm. (=Ixora pavetta Andr.) and Ixora undulata Roxb. During the recent floristic inventories in the Jaldapara National Park, an interesting species of Ixora was collected from the inland forests of Baniya, Kodalbasthi and Nalrajabadi areas. On critical scrutiny of collected specimens with literature (Bremekamp, 1959; Husain and Paul, 1989; Wood, 1999), and comparison with the type specimens at BSD and herbarium specimens of other Ixora species housed at CAL, it was identified as I. longibracteata Bremek., a species hitherto not reported from India. 95 Ta iwa nia Vol. 60, No. 2 Bremekamp (1959) described I. longibracteata based on a single flowering specimen (J.N. Dent 14) collected from Tintilla, Chittagong hill tracts in Bangladesh by J.N. Dent in 1939. In fact, the specimen was identified by Dent as Ixora goalparensis Bremek. Raizada (1941) also included this species in his article, “On the flora of Chittagong” based on the same collection. Since then there is neither a report of its occurrence from anywhere, including the Chittagong hill tracts nor a representative specimen available at any of the herbaria in Bangladesh, including the Bangladesh National Herbarium at Dhaka. Hitherto, this species is known to occur only from Chittagong hill tracts in Bangladesh based on a single collection of Dent. Therefore, the present collection is a rediscovery from other than its type locality about 75 years after its type collection from Chittagong hill tracts in Bangladesh. Detailed description, illustration, photographs and distribution map with status are provided here to facilitate its easy identification. Furthermore, the morphological features of the fruits are described in this paper for the first time. TAXONOMIC TREATMENT Ixora longibracteata Bremek., Indian Forester 85: 371. 1959; T. Husain & S.R. Paul, J. Econ. Taxon. Bot., Addit. Ser. 6: 119, f. 17. 1989. Figs. 1–3 Type: BANGLADESH, Tintilla, Chittagong hill tracts, 16 May 1939, J.N. Dent 14 (BSD, image!). Shrub, to 2 m high. Stems somewhat terete or to subangular, green or sometime maroon-tinged when young, cylindric and grey when mature; old twig somewhat longitudinally wrinkled; nodes swollen; internodes 2–7 cm long, distance reduces towards apex. Leave s si mp le, o p p o site -d ecussate, o b o vate, oblanceolate or oblanceolate-elliptic, cuneate at base, or lamina base narrowly forming a canal on petiole, entire and faintly thickened at margins, sometimes faintly wavy, especially towards apex, gradually tapering (when breadth is 1–3.5 cm) into a short-acuminate apex (abruptly acuminate when leaves obovate or broadly oblanceolate and breadth is 4–5.5 cm), 4.5–13.5 × 2– 5.5 cm, glabrous, dark green above, pale beneath; lateral veins 6–12 pairs, anastomosing near margins, a pair of faint veins one on either side of midrib gives an appearance of 3-veined base and forming an arch/margin and appear as an intramarginal vein; midrib raised on both surfaces, strongly so beneath, somewhat closely minute white granular gland-dotted beneath; petioles 4–11 mm long, canaliculated above, smooth, green, maroon-red/brown-red when young, rough, dark with annular scars below, canal closed when mature; stipules interpetiolar with broad triangular, concave base (2–2.5 × 1–2 mm) with grey 96 Fig. 1. Ixora longibracteata Bremek. A: Habit. B: Flower. C: Calyx lobe. D: Corolla lobe. E: Anther. F: Style. Figs. 1–3 soft hair and 5 or 6 thick hair (as long as the basal portion) closely adhering the surface and glandular inside, and a prolonged flexible cusp, green or slightly maroon-tinged; cusp 10–12 mm long. Inflorescence a kind of subcapitate cymes, axillary or terminal, ca. 4 × 5.5 cm, up to 6-branched; each branch further trichotomously branched into 3-flowered ultimate floral branches; peduncle of each primary branch 2–4.5 mm long, sparsely grey-puberulous; bracts with 2 linear arms with broad base, 2–2.5(–3) mm long with few long white hairs. Flower buds 1.2–1.7 cm long; corolla tube 1–1.5 cm long, 4-lobed; corolla lobe unopened portion linear-ovate-elliptic or linear-ovate-lanceolate, 3–3.5 × ca. 1 mm, white. Calyx tube ca. 1 mm long, glabrous, 5-lobed; lobes linear, 8–10 mm long, pink-tinged. Corolla salver-shaped, 1.8–2 × ca. 0.5 cm, glabrous, white; tube very faintly widening near lobes, 5-lobed; lobes oblong-ovate, thin at margins, acute to short-acuminate at apex, 4–5 × 1.5–1.75 mm, 8-veined. Stamens 4, alternating corolla lobes, 3.5–3.75 mm long; filaments adnate to junction of corolla tube and lobes, ca. 1.75 mm long; anthers oblong-lanceolate, shortly apiculate, ca. 2.5 mm long, pale yellow, dehiscing longitudinally on lateral sides; connective distinct; pollen 3-zonocolporate, subprolate, ca. 18 × 16 µm; tectum reticulate. Ovary inferior; style and stigma ca. 16 mm long; stigmatic lobes 2, slightly recurved June 2015 Karthigeyan and Arisdason: An addition to the flora of India Fig. 3. Distribution map of Ixora longibracteata Bremek. in India and Bangladesh. Fig. 2. Ixora longibracteata Bremek. A: Flowering-twig. B: Close-up of stipule. C: Inflorescence. D. Ripe fruits. E. Seed. F. SEM photograph of pollen. apically, ca. 2 mm long, dark-coloured. Drupes subglobose or ellipsoid, 10–11 mm across, circular scar at apex with erupted centre and remnants of calyx lobes; pericarp ca. 2 mm thick, succulent, glabrous, shiny, pale green when young, turning red when ripe; seed 1, ovoid, with a scar of point of attachment, 8.5–9 × ca. 7 mm, smooth, grey-brown. Flowering and Fruiting: May–December. Habitat and Ecology: Dense inland evergreen forests, at elevations between 80 and 100 m, growing with Chloranthus elatior Link and Psychotria calocarpa Kurz. Distribution: Bangladesh (Chittagong hill tracts) and India (Jaldapara National Park in West Bengal). Specimens examined: INDIA, West Bengal: Jalpaiguri district, Jaldapara National Park, Kodalbasthi Range, 5 June 2013, K. Karthigeyan 59347 [flowering specimen] (CAL); inland evergreen forest, Nalrajabadi, Chilapatha Range, 30 November 2013, K. Karthigeyan 61320 [fruiting specimen] (CAL); Baniya, Chilapatha Range, 11 May 2014, K. Karthigeyan 61491 [flowering specimen] (CAL). Conservation Status: Walter and Gillett (1998) and Rao et al. (2003) categorised it as an indeterminate species as the information on this species is inadequate. During the present study only five populations were located in the inland forests of Baniya (27 individuals), Kodalbasthi (4 individuals) and Nalrajabadi (10 individuals) areas in Jaldapara National Park. Following the IUCN Red List Categories and CriteriaVersion 3.1 (IUCN, 2012), this species has been assessed here as Critically Endangered [CR B1+2a, c (ii, iii, iv)] owing to its highly restricted geographical distribution (EOO: 16.9 km2; AOO: < 10 km2), fluctuations in geographic range of occurrence and number of locations and mature individuals in each population. Note: Bremekamp (1959) described I. longibracteata without fruits, and stated, ‘drupa nondum visa’ (fruits not yet seen). However, during the present study, fruiting specimens were also collected, and the description of fruits and seeds based on the recent collections are provided here for the first time with photographs. The species closely resembles I. goalparensis and I. subsessilis Wall. ex G. Don, however, it can easily be distinguished from them by number of flowers in an inflorescence, and size (especially in length) of bracteoles, calyx lobes, corolla tube and stamens. ACKNOWLEDGMENTS We are grateful to Dr. Paramjit Singh, Director, BSI and Dr. P. Lakshminarasimhan, Scientist & HoO, Central National Herbarium, Howrah (CAL), for facilities and encouragement, Dr. S.K. Srivastava, Scientist & HoO, BSI, Dehradun (BSD), for kindly providing the image of the type. We sincerely thank Dr. Tariq Husain, Scientist & Head, Herbarium & Angiosperm Taxonomy, National Botanical Research Institute, Lucknow, for his expert opinion, and Dr. Sarder Nasir Uddin, Senior Scientific Officer at Bangladesh 97 Ta iwa nia National Herbarium, Dhaka, for information on the specimens at Bangladesh National Herbarium. We are thankful to the Principal Chief Conservator of Forest, West Bengal and District Forest Officer, Wildlife Division III, Cooch Behar and Assistant Wildlife Warden, Jaldapara National Park, for their kind permission and support during the survey. Thanks are also due to Dr. C.R. Magesh, Preservation Assistant, CAL, Howrah, for help in preparing the map, Mr. G. Gnanasekaran, Botanical Assistant, MH, Coimbatore, for SEM photograph of pollen, and Mr. K. Dinesh Kumar, Chennai, for preparing photo plate. LITERATURE CITED Banerjee, L. K. 1993. Plant resources of Jaldapara Rhino Sanctuary. Botanical Survey of India, Calcutta. Barbhuiya, H. A., B. K., Dutta, A. K. Das and A. K. Baishya. 2012. Ixora rangonensis Bremek. (Rubiaceae): A new record for India. Taiwania 57(4): 413–417. Bremekamp, C. E. B. 1937a. The Malaysian species of the genus Ixora (Rub.). Bull. Jard. Bot. de Buitenzorg Sér. 3, 14: 197–367. Bremekamp, C. E. B. 1937b. The Ixora species of Burma and Andaman Islands. J. Bot. 75: 108–111; 169–175; 260–266; 295–298; 318–326. Bremekamp, C. E. B. 1938. The Ixora species of Burma and Andaman Islands – Additions and Emendations. J. Bot. 76: 330–336. Bremekamp, C. E. B. 1959. New Ixora species from Bengal, Burma and the Nicobar Islands. Indian Forester 85: 371– 375. Corner, E. J. H. 1941. Notes on the systematy and distribution of Malayan Phanerogams. IV. Ixora. Gard. Bull. Straits Settlem. 11: 177–235. Deb, D. B. and R. C. Rout. 1992. Two new species of Ixora (Rubiaceae subfam. Ixoroideae) from India and Burma. Kew Bull. 47: 295–300. Ghosh, C., T. K. Paul and A.P. Das. 2013. Rediscovery of Hibiscus fragrans Roxburgh (Malvaceae) from Jaldapara National Park in Duars of West Bengal, India. Pleione 7: 531–537. Hooker, J. D. 1880. The Flora of British India Vol. 3. L. Reeve & Co., London. pp. 137-149. Husain, T. and S. R. Paul. 1989. Taxonomic studies on Indian species of genus Ixora L. (Rubiaceae). J. Econ. Taxon. Bot., Addit. Ser. 6: 1–205. IUCN. 2012. IUCN Red List Categories and Criteria. Version 3.1. Second Edition. International Union for Conservation of Nature and Natural Resources, Gland. Linnaeus, C. 1753. Species Plantarum 1: 110. Laurentius Salvius, Stockholm. Mouly, A., S. G. Razafimandimbison, A. Khodabandeh and B. Bremer. 2009. Phylogeny and classification of the species-rich pantropical showy genus Ixora (Rubiaceae– Ixoreae) with indications of geographical monophyletic units and hybrids. Amer. J. Bot. 96: 686–706. Pradeep, A. K. 1997. Ixora sivarajiana, a new species of Rubiaceae from India. Nordic J. Bot. 17: 315–317. Raizada, M. B. 1941. On the flora of Chittagong. Indian Forester 67: 245–254. 98 Vol. 60, No. 2 Rao, C. K., B. L. Geetha and G. Suresh. 2003. Red list of threatened vascular plant species in India. Compiled from the 1997 IUCN Red List of Threatened Plants. ENVIS Centre for Floral Diversity, Botanical Survey of India, Howrah. Santapau, H. and A. N. Henry. 1973. A dictionary of the flowering plants in India. Council of Scientific & Industrial Research, New Delhi. Sivadasan, M. and N. Mohanan. 1991. Ixora agasthyamalayana, a new species of Rubiaceae from India. Bot. Bull. Acad. Sin. 32: 313–316. Walter, K. S. and H. J. Gillett (eds.). 1998. IUCN Red list of threatened plants. Compiled by the World Conservation Monitoring Centre. IUCN – The World Conservation Union, Gland. Wood, J. R. I. 1999. Ixora. In: Long, D.G. (ed.), Flora of Bhutan 2: 797–800. Royal Botanic Garden, Edinburgh and Royal Government of Bhutan.