First Record of a Rheophytic Species of Ixora (Rubiaceae) in India
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ISSN 1346-7565 Acta Phytotax. Geobot. 70 (1): 57–61 (2019) doi: 10.18942/apg.201816 shorT CommuniCaTion First Record of a Rheophytic Species of Ixora (Rubiaceae) in India 1 2,* 3 jaTindra sarMa , hussain ahMed barbhuiYa and sanTanu deY 1Research, Education and Working Plans, Assam Forest Department, Aranya Bhawan, Panjabari, Guwahati, Assam 781037, India; 2Landscape and Cosmetic Maintenance Section, Architectural and Structural Engineering Division, Bhabha Atomic Research Centre, Trombay, Mumbai, Maharashtra-400085, India. * [email protected] (author for correspondence); 3Department of Botany, Nagaland University, Lumami, Nagaland 798627, India Ixora yunnanensis (Rubiaceae) is recorded for the first time in India. Previously, it was considered en- demic to Yunnan Province, China. The present report extends its distribution range ca. 760 km west- ward. A brief description of the plant along with photographs and a distribution map are provided to fa- cilitate its unambiguous identification in the future. Key words: flora of India,Ixora yunnanensis, new locality, rheophyte Ixora L. (Rubiaceae), comprising about 530 ted on rocks, show sympodial branching and bear species of shrubs and trees (Davis et al. 2009), is short petiole, glabrous, narrow leaves with entire the third largest genus in the family. It is wide- margins (van Steenis 1981, 1987). Ixora yunna- spread in tropical Africa, America, Asia, Mada- nensis Hutch. was first described by Hutchinson gascar, and the Pacific islands (Chen & Taylor (1916) based on a collection made by Dr. Augus- 2011, De Block 2014). Ixora is easily recognized tine Henry (1857–1930) from the banks of the by its articulate petioles, trichotomously branched Red River (Hong He) in Yunnan Province, China. terminal inflorescences, narrowly tubular 4-mer- Until now, it was considered to be endemic to ous flowers with contorted aestivation, 2–4-lobed Yunnan Province (Chen & Taylor 2011). stigma, 2–4-locular ovary with a single ovule per During field explorations (2016–2018) in the locule, drupaceous fruits and seeds with a large Koka, Panimur, Amreng and Zirikindeng regions adaxial excavation (De Block 1998). In India, the of West Karbi Anglong District of Assam, the se- genus is represented by ca. 50 species (Hooker nior author found a rheophytic shrub in rock 1880, Bremekamp 1937, 1938, 1959, Husain & crevices at the edge of the Kopili River near Paul 1986, 1989, 1991, Sivadasan & Mohanan Koka. After examining specimens and consult- 1991, Deb & Rout 1992a, b, Pradeep 1997, Barb- ing the literature we identified the plant as Ixora huiya et al. 2012, Murugan & Prabhu 2014, yunnanensis, a new addition to the Rubiaceae of Karthigeyan & Arisdason 2015, Balan & Shan- India and an extension of its range ca. 760 km mugam 2016). Chowdhury (2005) listed 8 species westward. A description of the plant (based on from Assam. Indian materials) along with photographs and a Rheophytes are plants that are confined to the distribution map are provided to facilitate future bed of swift-running streams and rivers and grow identifications. up to the high water level, but not beyond the reach of regularly occurring flash floods. Rheo- phytic land plants are either herbs or shrubs. Ixora yunnanensis Hutch. in Sargent, Pl. Wil- Shrubby rheophytes usually have their roots mat- son. 3(2): 412 (1916); T. Chen & C. M. Taylor, Fl. 58 Acta Phytotax. Geobot. Vol. 70 Fig. 1. Ixora yunnanensis Hutch. A, Habit. B, Close up of inflorescence. C, Late inflorescence showing calyx. D, Twig of plant with inflorescence. E, Single flower. F, Top view of flower showing corolla lobes and bearded throat of corolla tube. G, Apex of flower showing corolla lobes and stigma. H, Inflorescence. All based on J. Sarma s.n. (HBARC). February 2019 sarMa & al–First record of lxora in lndia 59 Fig. 2. Distribution map of Ixora yunnanensis Hutch. Square (■) indicates previously known localities; solid circle (●) indi- cates currently reported locality. Map was created with SimpleMappr, http://www.simplemappr.net (Shorthouse 2010). China 19: 182 (2011) ––Fig. 1 congested cymose, ca. 6.5 × 5 cm; peduncle gla- brous, terete, to 1.3 cm long, 1.8–2.2 mm in Type: CHINA. Yunnan, Hsin-Kei (XinKai), Red Riv- er, A. Henry 9585 (holo- K-000763128 image!; iso- NY- diam.; bracts narrowly lanceolate, ca. 6 × 0.6 00131977 image!); Red River banks, Manpan, A. Henry mm, base occasionally 1 or 2 dentate, apex acu- 10370 (para- K-000763129 image!). minate. Flowers sessile to short pedicellate; pedi- Additional specimens examined. INDIA. Assam, cels up to 3 mm long. Calyx glabrous, turbinate; West Karbi Anglong, Panimur, Koka, on the edges of Ko- hypanthium obconical to slightly cupuliform, pili riverbed, 25°44ʹ09.91″ N, 92°49ʹ15.1″E, 81.59 m msl, 1.7–2 mm long and ca. 1.7 mm wide at mouth; 8 May 2017, J. Sarma s.n. (HBARC-00006395, 00006396, limb deeply 4-lobed; lobes linear-lanceolate, 3–4 00006397). CHINA. Yunnan, Lüchun, Huanglianshan, 24 October 1995, S. K. Wu et. al. 222 (KUN-0770434 im- × 0.7–1 mm, apex subacute to acute. Corolla age); Huanglianshan, 30 October 1995, S. K. Wu et. al. white; tube 20–35 mm long, slightly dilated up- 789 (KUN-0770435 image); Hekou Yao Autonomous wards, 1.0–1.5 mm in diam., white bearded at County, 23 May 1953, K. H. Cai 1119 (PE-00737441 im- throat; lobes 4, narrowly elliptic-oblong, 7.5–8.2 age); Kafang, 25 May 1953, K. H. Cai 1156 (IBSC- × 3.0–3.5 mm, apex obtuse. Stamens 4, exserted, 0443331 image). alternate to corolla lobes; anthers dorsifixed near Shrub, usually 60–70 cm tall. Stems glabrous, base, oblong, 4.2–4.6 × 0.8–1 mm, base slightly sparsely branched. Leaves opposite; petiole 0.5– cordate, apex acute; filament 1.3–1.5 mm long, 1.6 cm long, glabrous; blade lanceolate to narrow- glabrous, basally adnate to throat of corolla tube. ly oblanceolate, 5.5–15 × 0.6–2 cm, glabrous on Ovary glabrous, 2-locular, 1.4–1.6 mm in diam.; both surfaces, base attenuate, apex acute to long style ca. 36 mm long, exserted from corolla tube; acuminate; lateral veins 10–15 pairs; stipules in- stigma slightly fusiform, apex bilobed, lobes un- terpetiolar, persistent, basally united around the equal, ca. 2.2 mm long. Fruits and seeds not seen. stem, triangular to broadly ovate, 3–4 × 2.9–3.3 mm, adaxially glabrous, abaxially villous with Flowering. April–May. brown colleters, apex acute or aristate, arista usu- ally 2.5–3 mm long. Inflorescences terminal, Ecology and Habitat. Ixora yunnanensis is a subsessile to short pedunculate, corymbiform to rheophyte among rocks at the edges of rivers 80– 60 Acta Phytotax. Geobot. Vol. 70 102 m above sea level in Koka, Assam, India, tantly, we are indebted to two anonymous reviewers for where it grows near fast flowing water. The leaves their constructive comments on the manuscript. of Ixora yunnanensis shows typical characteris- tics of a rheophyte; short petiole, glabrous and narrow leaf blades with entire margins. Associ- ated rheophytes are Syzygium cyanophyllum, S. References polypetalum (Myrtaceae), Carissa sp. (Apocyna- ceae), Eriobotrya angustissima (Rosaceae), Pa- Balan, A. P. & H. Shanmugam. 2016. Ixora predeepii, a vetta sp. and Tarenna pumila (Rubiaceae). new species of Rubiaceae from southern Western Ghats, India. Bangladesh J. Plant Taxon. 23: 65–69. Barbhuiya, H. A., B. K. Dutta, A. K. Das & A. K. Baishya. Distribution. India (Assam: West Karbi An- 2012. Ixora rangonensis Bremek. (Rubiaceae): A new glong-Koka, present record), China (Yunnan: record for India. Taiwania 57: 413–417. Along Red River Banks, Hsin-Kei (XinKai), Bremekamp, C. E. B. 1937. The Ixora species of Burma Manpan, Lüchun, Mt. Huanglianshan, Hekou and Andaman Islands. J. Bot. 75: 108–111, 169–175, 260–266, 295–298, 318–326. Yao Autonomous County, Kafang, Xishuangban- Bremekamp, C. E. B. 1938. The Ixora species of Burma na, Mengla) (Hutchinson 1916, CVH 2018) (Fig. and Andaman Islands. – Additions and Emendations. 2). J. Bot. 76: 330–336. Bremekamp, C. E. B. 1959. New Ixora species from Ben- Taxonomic note. Ixora yunnanensis can be gal, Burma and the Nicobar Islands. Indian Forester 85: 371–375. easily distinguished from other species of Ixora Chen, T. & C. M. Taylor. 2011. Ixora Linnaeus. In: Wu, Z. by its extremely narrow oblanceolate leaves and Y., P. H. Raven & D. Y. Hong, (eds.), Flora of China, longer calyx lobes. It is similar to I. subsessilis vol. 19, pp. 177–182. Science Press, Beijing, and Mis- Wall. ex G. Don of India, China and Thailand in souri Botanical Garden Press, St. Louis. having subsessile inflorescences, but I. subsessi- Chowdhury, S. 2005. Assam’s Flora (Present Status of Vascular Plants). Assam Science Technology and En- lis is distinct from I. yunnanensis in having ellip- vironment Council, Guwahati. tic-lanceolate leaves up to 8.3 cm wide, shorter CVH, 2018. Chinese Virtual Herbarium. Institute of Bot- triangular calyx lobes up to 2 mm long and a gla- any, Chinese Academy of Sciences, Beijing, China. brous corolla tube. Moreover, I. subsessilis is <http://www.cvh.org.cn.> [Accessed Aug. 04, 2018]. more vigorous than I. yunnanensis. Ixora subses- Davis, A. P., R. Govaerts, D. M. Bridson, M. Ruhsam, J. Moat & N. A. Brummitt. 2009. Global assessment of silis usually grows on hill slopes between 60 and distribution, diversity, endemism, and taxonomic ef- 1,800 m above sea level and is either a shrub or a fort in the Rubiaceae. Ann. Missouri Bot. Gard. 96: small tree up to 2.4 m tall (Husain & Paul 1989). 68–78. Ixora yunnanensis in India varies slightly from Deb, D. B. & R. C. Rout. 1992a. Two New Species of Ixo- the plants in China in having only opposite leaves ra (Rubiaceae subfam.