Telopea Volume 18: 425-431 The Royal Publication date: 30 September 2015 Botanic Gardens Journal of Plant Systematics dx.doi.org/10.7751/telopea8907 & Domain Trust plantnet.rbgsyd.nsw.gov.au/Telopea • escholarship.usyd.edu.au/journals/index.php/TEL • ISSN 0312-9764 (Print) • ISSN 2200-4025 (Online) Christisonia mira (Orobanchaceae): A new plant species from Southern Western Ghats, India Jose Mathew and Kadakasseril V. George 13 2 School of Environmental Sciences, Mahatma Gandhi University, Kottayam, Kerala, India 2NKP Vaidyar Ayurvedic Research Foundation, Kadavanthra, Cochin, Kerala, India 3Author for correspondence: [email protected] Abstract A root parasitic plant, Christisonia mira J.Mathew (Orobanchaceae) is described as a new species from the Kerala part of southern Western Ghats, India. Introduction Christisonia Gardner is an achlorophyllous (holoparasitic) genus comprising c. 17 species distributed in India, Sri Lanka, Laos, SW China, Thailand and Malesia (Nickrent 2012). According to Benniamin et al. (2012), ten species of Christisonia have been recorded in India, of which, six species viz., C. bicolor Gardner, C. calcarata Wight, C. indica Anil Kumar, C. keralensis Erady, C. neilgherrica Gardner and C. tubulosa (Wight) Hook.f. are recorded from the Kerala part of the Western Ghats (Nayar et al. 2014). Sasidharan (2013) indicated that C. indica and C. tubulosa are endemic to the southern Western Ghats; C. bicolor and C. neilgherrica (=Campbellia cytinoides Wight) are Indo-Sri Lanaka linkage taxa; C. calcarata is a south Indian element and, C. keralensis is a southern Western Ghats, north east element. Mathew and George (2015) recently added C. tomentosa J.Mathew Sc K.V.George, as new from the Kerala part of southern Western Ghats. Botanical explorations in the Achankovil forests during 2009-2014 yielded specimens of Christisonia that we feel are sufficiently distinctive to warrant taxonomic recognition as a new species. Christisonia mira J.Mathew is here described and illustrated. Taxonomy Christisonia mira J.Mathew, sp. nov. (Figs 1-4) Diagnosis: Christisonia mira is morphologically most similar to C. bicolor Gardner, but differs from that species in having: a red, 4 cm long corolla (corolla yellow, 6 cm long in C. bicolor); bracteoles elliptic to oblanceolate, 5 mm long (8 mm long, lanceolate or acute in C. bicolor); racemes of 8 or 9 flowers (racemes of 5 or 6 flowers in C. bicolor), and stamens non didynamous and 2.5-2.7 cm long (stamens didynamous, 3-3.5 cm long in C. bicolor). C. mira is also morphological similar, with similar ecological preferences to those of C. tomentosa and C. neilgherrica but differs from these species as indicated in Table 1. Type: India, Western Ghats, Kerala, Kollam district, Vellakkaltheri, altitude 1800 m, 9°07'H" N, 77°13'05" E, 9 Jun 2012, Jose Mathew 3076 (holo: MH; iso: TBGT). © 2015 Royal Botanic Gardens and Domain Trust 426 Telopea 18: 425-431, 2015 Mathew and George Te^'CT'E 77"3rj'tr'E 77 “i:rU"E 77 WE Periya/ RAer (OWN- 10'?0"N Muvattupiizfia Rfmr J' Minachil Rh/er 9“3(JCi"H -a^BfO"N Pamba River \ Ac/)ar>frow7 Wi/er Achanhovil Division Kaiiada River BfOItTN- sid'crN State Boundary River Achenkovii Division Protected Area Forest Kr In meters 12.5 25 Water Bodies -<-1- i<. T&HJ'CJ'E 77 WE 77 “iBCl'Cf' E Fig. 1. Christisonia mira extent of currently known distribution in the Kollam district of the Western Ghats, India. Herbs, erect to 5-6 cm, achlorophyllous, parasitic on the roots of Strobilanthes luridus Wight., hairy. Roots very numerous, wiry, profusely branched, up to 1.5 mm thick, with haustoria at the place of contact with the host roots and developing many adventitious buds. Stem unbranched, with whorled, oblanceolate bracts. Inflorescence racemose, 8- or 9-flowered. Bracts 5 mm long, 2-3 mm wide, light brownish, glabrous. Pedicels 1 cm long, 3-5 mm thick, erect, pink. Bracteoles 2, elliptic to oblanceolate, 5 mm long, 3 mm wide. Flower buds glandular hairy, covered with copious translucent tasteless slime when young. Calyx 5, 1.2 cm long, 0.6- 0.8 cm wide, base creamy white, lobs red, tubular-campanulate with slight median zygomorphy, tube split at the top to one third the length into 5 subequal triangular valvate lobes with acute apex. Corolla tube 3-3.5 cm long, red-coloured, trichomes on both sides, lower half closely appressed to the ovary, upper half inflated; throat yellowish with a tinge of orange; tube expanding into a sub-bilabiate 5-lobed limb; lobes 0.8-1 cm long, orbicular reniform, imbricate, anterior three lobes somewhat equal and slightly smaller than the posterior lobes. Stamens 4, inserted at the constricted part of the corolla tube, included, non didynamous; filaments light purplish, 2.5-3 cm long, glandular hairy throughout; anthers pale purplish, two-celled, one of the cells fertile, ovate, base sharply spurred with tip curved outwards; connective with a prominent swelling on one side. Pollen grains with smooth wall. Ovary of 2 median carpels, syncarpous, superior, unilocular with a tendency to become bilocular at the base; placentae 2, parietal, bipartite, tips expanding into fleshy portions; ovules 180- 200 pm long, 125-150 pm broad, numerous, anatropous and arising from the entire surface of the placenta; style glabrous, 3-3.5 cm long, included but reaching above the level of the anthers; stigma peltate and with a narrow depression in the centre. Fruit a capsule, pyriform, ca 1.4 x 1.8 cm, unilocular, enclosed by persistent calyx. Seeds minute, numerous. Other specimen examined: INDIA: Kerala: S Western Ghats, Kollam district, Vellakkaltheri, 9 Jun 2013, Jose Mathew 3094, 3095 (TBGT). Etymology: The specific epithet mira refers to the wonderful appearance of this new species. Distribution and ecology: Christisonia mira is endemic to the Southern Western Ghats, currently known only from two localities from Vellakkaltheri in the Kollam district (Fig. 1). The species grows on the wet roots of Christisonia mira: A new plant species from India Telopea 18: 425-431, 2015 427 Strobilanthes luridus Wight at altitudes of c. 1800 m. It is found in association with Ophiopogon intermedius D.Don (Asparagaceae) and Elatostema acuminatum (PoirJ Brongn. (Urticaceae). Flowering: Flowers and fruits in June. Conservation status: Christisonia mira is currently known only from 2 localities of Achankovil reserve forest area (Vellakkaltheri in the Kollam district), each separated by 800 m. A total of 90 mature individuals were found in the area. The data gained from the field studies were evaluated according to the IUCN (2015) categorization and at least “vulnerable” status has been proposed for the species. Remarks: Christisonia mira is a holoparasite growing on the roots of Strobilanthes luridus. Christisonia tomentosa, also grows on the roots of the same host at northern Achankovil. Strobilanthes luridus is an endemic species, occupying a very restricted area in the evergreen forests of southern Western Ghats (Sasidharan 2013). Thorogood et al. (2007) evinced that host specificity is a driving force in the evolution and speciation of parasitic plants. An enhanced understanding of the evolution, cell biology, and physiology of host specificity in this, and related taxa is crucial. Key to the Christisonia in southern Western Ghats 1. Anthers not spurred.7 1. Anthers spurred.2 2. Inflorescence 15-26 cm long, flowers loosely arranged in racemes. C. tubulosa 2. Inflorescence up to 10 cm long, flowers compactly arranged in racemes.3 3. Racemes of 3 or 4 flowers; calyx 1.7-2 cm wide, conceals most of corolla-tube. C. indica 3. Racemes of >5 flowers; calyx campanulata, up to 1.5 cm wide, conceals 1/3 of corolla tube.4 4. Corolla lobes white or cream.5 4. Corolla lobes red or yellow.6 5. Pedicels as long as the calyx or shorter. C. calcarata 5. Pedicels longer than the calyx (3 cm long) . C. keralensis 6. Stamens not didynamous, anthers elliptic to oblanceolate; corolla throat orange-tinged .C. mira 6. Stamens perfectly didynamous, anthers lanceolate or acute, corolla throat concolourous with corolla tube . .C. bicolor 7. Corolla lobes red, stamens didynamous . C. tomentosa 7. Corolla lobes yellow, stamens equal in length.C. neilgherrica 428 Telopea 18: 425-431, 2015 Mathew and George M 7 * Fig. 2. Christisonia mira: a,b, plants in natural habitat. /. Mathew 3076. Photograph: J. Mathew Christisonia mira: A new plant species from India Telopea 18: 425-431, 2015 429 Fig. 3. Christisonia mira: a, unopened flowers with hairs; b, flowers. /. Mathew 3076. Photograph: J. Mathew 430 Telopea 18: 425-431, 2015 Mathew and George Fig. 4. Christisonia mira: a, opened flower; b, inflorescence; c, flower showing stamens and peltate stigma; d, flower bracts and bracteoles; e, Stamen with spurred anthers and stigma with depressed cavity; f, fruit. /. Mathew 3076. photograph: J. Mathew. Christisonia mira: A new plant species from India Telopea 18: 425-431, 2015 431 Table 1. Ecological and morphological differences between Christisonia mira, C. bicolor, C. tomentosa and C. neilgherrica Character C. mira G bicolor C. tomentosa C. neilgherrica Host Strobilanthes luridus Strobilanthes spp. Strobilanthes luridus shrubs Incl. S. lurid us Height 5-6 cm 8-12 cm 5-6 cm 5-6 cm Flowers per 8-9 5-6 10-12 10-12 inflorescence Bracteoles elliptic—oblanceolate, lanceolate or acute, elliptic—oblanceolate, lanceolate or acute, 5 mm 8mm 5 mm 8-10 mm Corolla colour and red, 3-3.5cm long yellow, 6 cm long red, 4 cm long yellow, 6 cm long tube length Colour corolla throat yellow to orange yellow red yellow Stamen form and purple, non- yellow, didynamo us red, didynamous yellow, non- filament colour didynamous didynamous Anthers Pale purple, spurred white, spurred purplish, not spurred white, not spurred Acknowledgments The first author is thankful to Dr CT Aravindkumar, Director, School of Environmental Sciences, M. G. University, Kottayam, Kerala for suggestions and encouragement. The first author greatly benefited from the help of Dr Murray J Henwood (SYD). The authors are thankful to the curator at TBGT, Thiruvanthapuram, Kerala for consultations, and the Kerala Forest Department for permission to conduct research. 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(Department of plant Biology, Southern Illinois University, Carbondale, Illinois, USA) http://www.parasiticplants.siu.edu/listparasites. html (accessed 10 July 2013) Sasidharan N (2013) Flowering plants of Kerala: CD-ROM ver. 2.0. (Kerala Forest Research Institute, Peechi, Kerala) Thorogood CJ, Rumsey FJ, Hiscock SJ (2007) Speciation and host specificity in Orobanche. In. Proceedings of the IPPS 9th World Congress on Parasitic Plants. June 3. (Charlottesville, Virginia, United States) Manuscript received 16 July 2015, accepted 24 September 2015