A new distribution record for the Critically Endangered Madura Swampweed Hygrophila madurensis (N.P. Balakr. & Subr.) Karthik. & Moorthy (Acanthaceae)

 

P. Raja 1, S. Soosairaj 2, N. Dhatchanamoorthy 3 & A. Kala 4

 

1,2,3,4 Department of Botany, St. Joseph’s College (Autonomous), Tiruchirappalli, Tamil Nadu 620002, India

1 raja.plantbiology@gmail.com, 2 pspsoosai@yahoo.co.in (corresponding author), 3 dhatcha@gmail.com, 4 akalabot7@yahoo.in

 

 

doi: http://dx.doi.org/10.11609/JoTT.o4015.7581-3

 

Editor: N.P. Balakrishnan, Retd. Joint Director, BSI, Coimbatore, India. Date of publication: 26 July 2015 (online & print)

 

Manuscript details: Ms # o4015 | Received 09 May 2014 | Final received 04 May 2015 | Finally accepted 26 June 2015

 

 

Citation: Raja, P., S. Soosairaj, N. Dhatchanamoorthy & A. Kala (2015). A new distribution record for the Critically Endangered Madura Swampweed Hygrophila madurensis (N.P. Balakr. & Subr.) Karthik. & Moorthy (Acanthaceae). Journal of Threatened Taxa 7(9): 7581–7583; http://dx.doi.org/10.11609/JoTT.o4015.7581-3

 

Copyright: © Raja et al. 2015. Creative Commons Attribution 4.0 International License. JoTT allows unrestricted use of this article in any medium, reproduction and distribution by providing adequate credit to the authors and the source of publication.

 

Funding: None.

 

Competing interests: The authors declare no competing interests.

 

Acknowledgements: The authors are thankful to Director and officers-in charge of MH, Coimbatore for providing facilities and support. We also thank the forest officials of Pudukkottai District.

 

 

The Flora of British India reported 49 genera, 504 species and 127 varieties of Acanthaceae from India (Clarke 1885). The recent report in “Flowering Plants of India”by Karthikeyan et al. (2009) listed 47 genera, 475 species and 118 varieties of Acanthaceae in India. The genus Hygrophila R.Br. belongs to the family Acanthaceae and comprises about 100 species (Hai & Huyen 2012), of which many are aquatic plants (Deng et al. 2011). Clarke (1885) reported eight species under the genus Hygrophila from India. Later Gamble (1924) listed four species in the Flora of the Presidency of Madras. Matthew (1983) reported four species in the Flora of the Tamil Nadu Carnatic. Henry et al. (1987) listed six species of Hygrophila in the Flora of Tamil Nadu, while retaining Santapaua as an independent genus.

During botanical explorations in Pudukkottai District of Tamil Nadu in December 2013. Hygrophila madurensis (N.P. Balakr. & Subr.) Karthik. & Moorthy (Acanthaceae) was collected from marshy localities. This species is listed as Critically Endangered and endemic to Tamil Nadu found along the foothills of the Eastern Ghats section (Walter & Gillett 1998; Arisdason 2011). The type specimen was collected from Nallakulam in Alagar Hills, Madurai District of Tamil Nadu on 12 February 1958. After the type collection, this was collected only once by Ravikumar in 1984 (IUCN 2013). Balakrishnan & Subramanyam (1963) described the genus Santapaua with only one species, namely Santapaua madurensis. Taking into consideration the broader concept of the genus Hygrophila as suggested by various authors, encompassing several related genera like Adenosma, Asteracantha, Cardanthera, Hemiadelphis, Nomaphila and Synnema, Karthikeyan & Moorthy merged the genus Santapaua with Hygrophila. Therefore, if Hygrophila is treated as sensu lato, this species should now be known by the name Hygrophila madurensis (N.P. Balakr. & Subr.) Karthik. & Moorthy (Arisdason 2013). The present sighting at Pudukkottai plains is a new distribution record from Tamil Nadu. This paper provides a brief description, distribution, illustration and photographic images for a better understanding of the species.

 

 

Hygrophila madurensis

(N.P. Balakr. & Subr.) Karthik. & Moorthy

(Images 1–2)

 

In Flowering Plants of India Dicotyledons (Acanthaceae - Avicenniaceae) 1: 22. 2009. Santapaua madurensis N.P. Balakr. & Subr. in J. Indian Bot. Soc. 42: 411. 1963; Henry et al., Fl. Tamil Nadu, India series I: Analysis, 2: 160, 1987.

Specimen examined: SJCBOT3329, Kudumiyanmalai, Pudukkottai District, Tamil Nadu 17.xii.2013, coll. P. Raja and identified by S. Soosairaj, Dept. of Botany, St. Joseph’s College, Tiruchirappalli and confirmed by matching with isotype (Subramanyam 5286 B-C) at the Madras Herbarium (MH), Botanical Survey of India, Southern Regional Centre, Coimbatore (Image 3).

Description: Herbs, 10–20 cm high; branchlets decumbent, arising from base, stems quadrangular with raphides arranged longitudinally, swollen at nodes. Leaves thin, membranous, glabrous, oblong, lanceolate, oblanceolate, base cuneate, margin minutely crenulate, acute or subacute at apex, nerves 5–7 pairs, prominent below; rhaphides scattered on upper surface, petioles up to 2.5mm long. Flowers in axillary open dichasial cymes becoming sympodial and unilateral; primary peduncle ca. 5mm long; internodes ca. 3mm long; bracts linear, acute, 2–5 mm long; pedicelsca 1mm long. Calyx-lobes 5, free, sub equal, linear, acute, 4–5×1 mm. Corolla purple, ca. 0.9×0.5 cm across; tube funnel-shaped, broad, pubescent inside; upper lip bifid emarginate, lobes rounded; lower lip trifid, lobes obtuse, rounded. Stamens 4, fertile, didynamous, filaments linear, filiform, glabrous, 2–4 mm long; anthers oblong, ellipsoid, 1–1.3 mm long. Ovary pubescent, ca. 2mm long, oblong–elliptic, 2-celled; ovules many; style linear, 4mm long; stigma simple. Capsules linear-oblong, flat, sessile, ca. 7×1 mm; seeds bearing throughout the length of the capsule; retinacula minute, conical, straight, slender. Seeds 10–40, small, ellipsoid, compressed, glandular puberulous.

Habitat: Marshy localities along edges of seasonal ponds.

Flowering & fruiting: December–January.

Distribution: Endemic to Tamil Nadu (Madurai, Pudukkottai).

 

 

 

References

 

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Balakrishnan, N.P. & K. Subramanyam (1963). A New Genus of Acanthaceae from Peninsular India. Journal of the Indian Botanical Society 42: 411–415.

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