Bergia cuddalorensis S. Soosairaj, sp. nov. (Elatinaceae), a new species from Tamil Nadu, IndiaBergia cuddalorensis sp. nov. (Elatinaceae), a new species from IndiaJoseph LINCYhttps://ror.org/02w7vnb600000-0002-0296-3658Sebastian SOOSAIRAJhttps://ror.org/02w7vnb600000-0002-7429-61102025-01-07T09:38:00Muséum national d'Histoire naturelle15/7/20244/9/20241-613/1/202547 (1)13/1/202510.5252/adansonia2025v47a1

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border:0.75pt solid #000000;ElatinaceaeBergiaIndiaTamil Nadunew species.ElatinaceaeBergiaIndeTamil Naduespèce nouvelle.RévisionBergia cuddalorensis S. Soosairaj, sp. nov. (Elatinaceae), a new species from Tamil Nadu, IndiaJoseph LINCYDepartment of Botany, St. Joseph’s College (Autonomous),(affiliated to Bharathidasan University, Tiruchirappalli),Tiruchirappalli, Tamil Nadu (India)Sebastian SOOSAIRAJDepartment of Botany, St. Joseph’s College (Autonomous),(affiliated to Bharathidasan University, Tiruchirappalli),Tiruchirappalli, Tamil Nadu (India)

ABSTRACT. Bergia cuddalorensis S. Soosairaj, sp. nov. a new species from Tamil Nadu, India, has some distinct characteristics that set it apart from other related species like B. trimera Fisch. & C.A. Mey., B. ammannioides Roxb., and B. suffruticosa (Delile) Fenzl. It can be distinguished by the number of stamens, the shape of sepals, leaves and stipules as well as trichome features. A key to the Indian species of Bergia L. is provided.

KEYWORDS: Elatinaceae, Bergia, India, Tamil Nadu, new species.

RÉSUMÉ. Bergia cuddalorensis S. Soosairaj, sp. nov. une nouvelle espèce du Tamil Nadu, Inde, présente des caractéristiques distinctes qui la distinguent d’autres espèces apparentées comme B. trimera Fisch. & C.A.Mey., B. ammannioides Roxb. et B. suffruticosa (Delile) Fenzl. Elle se distingue par le nombre d’étamines, la forme des sépales, des feuilles et des stipules ainsi que par la morphologie des trichomes. Une clé des espèces indiennes de Bergia L. est fournie.

MOTS CLÉS: Elatinaceae, Bergia, Inde, Tamil Nadu, espèce nouvelle.

INTRODUCTION

Bergia, a genus within the Elatinaceae family, was first described by Linnaeus in 1771, honouring Petrus Jonas Bergius, a pupil of Linnaeus (Leach 1989). With 29 species worldwide it is mainly found in tropical and subtropical regions, with Africa and Australia hosting the highest diversity as centres of diversity (POWO 2024). In India, there are seven species, with Tamil Nadu hosting three (Nair & Henry 1983, Britto 2019). However, confusion persists in Indian literature regarding the distinction between B. ‌ammannioides ‌Roxb. and B. ‌trimera ‌Fisch. & C.A. Mey. Often, the latter taxon is overlooked. Leach (2021) clarifies this issue, noting that B. ‌ammannioides features 5-merous flowers, while B. ‌trimera exhibits 3-4-merous flowers.

While undertaking a botanical survey in Cuddalore district of Tamil Nadu, the authors have collected a specimen of Bergia. The identity of this specimen was traced with the help of published literature, local floras, online databases and herbarium collections at various herbaria. After consulting these sources it was found to be unknown to science and hence it is described as a distinct new species.

MATERIAL AND METHODS

The authors are conducting a comprehensive survey of the flora in the Cuddalore district for a doctoral degree since 2019. Methodology involves frequent field exploration to collect plant specimens, which are then processed using standard herbarium techniques. During one of these surveys, they discovered an intriguing herb in a dried pond near Veppur (Fig. 1). Identity of the taxon underwent a thorough literature screening using local floras (Thiselton Dyer 1885; Sohmer 1980; Matthew 1983; Nair & Henry 1983; Bhattacharya 1993; Britto 2019), published literature (Leach 1989, 2021), the study of herbarium specimens deposited at MH, CAL and RHT, consultation with various online databases such as Kew Data Portal (http://data.kew.org), GBIF (http://www.gbif.org), POWO (https://powo.science.kew.org/), and online floras including eflora of China (http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=103833), Kerala plants (http://www.keralaplants.in) and Flora of Peninsular India (http://flora-peninsula-indica.ces.iisc.ac.in/).

TAXONOMIC TREATMENT

Key to Indian species of Bergia L.

1. Plants pubescent ⇒ 2— Plants glabrous ⇒ 52. Petals 3, sepals 3; stamens 3 ⇒ B. ‌trimera ‌Fisch. & C.A. Mey.— Petals 5, sepals 5; stamens 5-10 ⇒ 33. Stamens 5; flowers > 15 per node ⇒ B. ‌ammannioides ‌Roxb.— Stamens 10; flowers < 10 per node ⇒ 44. Perennial; aromatic; leaves sessile, pubescent; petals obtuse ⇒ B. ‌suffruticosa ‌(Delile) Fenzl— Annual; nonaromatic; leaves petiolate, glabrous; petals acute, mucronate ⇒ B. ‌cuddalorensis ‌S. Soosairaj ‌sp. nov.,5. Undershrub; stipules glandular; sepals denticulate; style straight ⇒ B. ‌aestivosa ‌(Wight & Arn.) Steud.— Herb; stipules eglandular; sepals entire; style recurved ⇒ 66. Plants succulent; stipules pectinate; flowers in a cluster ⇒ B. ‌capensis L.— Plants not succulent; stipules fimbriate; flowers solitary or in pairs ⇒ B. ‌polyantha ‌Sond.‌ Elatinaceae ‌Dumort.‌ Bergia L.
Bergia ‌cuddalorensis ‌S. Soosairaj ‌sp. nov.,

(Figs 2; 3)

Diagnose

B. ‌cuddalorensis ‌S. Soosairaj ‌sp. nov., can be distinguished from B. ‌suffruticosa ‌(Delile) Fenzlas a nonaromatic erect herb (vs aromatic shrub), with glabrous leaves and stipules (vs pubescent), a mucronate apex of the petals (vs obtuse) and a vesicular seed surface (vs smooth). The morphology of B. ‌cuddalorensis ‌S. Soosairaj ‌sp. nov., closely resembles B. ‌ammannioides ‌Roxb. but can be differentiated by having glabrous leaves and stipules (vs pubescent), a mucronate apex of the petals (vs obtuse), 6-10 flowers per node (vs c. 30 flowers per node) and seed surface vesicular (vs reticulate) (Table 1).

Type material

India•2 specimens; Tamil Nadu, Cuddalore district, Veppur, Lathur Forest; 11°28’04.72”N, 78°57’57.93”E; alt. c. 90 m; 26.I.2023; S. Soosairaj 7816; holo-, RHT!; iso-, MH!

Etymology

The species epithet is based on the collection locality of the type specimen in Cuddalore district of Tamil Nadu, India.

Distribution

The species is known from the state of Tamil Nadu at the type location in Cuddalore district and also a single location in Pudukkottai district.

Phenology

Flowering and fruiting January-March.

Ecology

It is an annual species that thrives in wet environments, specifically in ponds in clay soils after the water has drained and in cultivated fields after harvest. It is found growing in association with Ammania ‌verticillata ‌(Ard.) Lam., Vahlia ‌digyna ‌(Retz) Kuntze, Epaltes ‌divaricata (L.) Cass., Hoppea ‌dichotoma ‌Willd., Exacum ‌pedunculatum L., Lindernia ‌dubia (L.) Pennell and Rotala ‌verticillaris L.

Conservation status

B. ‌cuddalorensis ‌S. Soosairaj ‌sp. nov., is reported from only two locations and further exploration is needed to study the actual distri­bution in similar habitats, hence, it is categorized as ‘data deficient’ (DD) under the IUCN (2019) conservation status.

Additional specimens examined

India•1 specimen; Tamil Nadu, Pudukkottai district; 10°31’42”N, 78°47’06”E; alt. c. 150 m; 14.II.2024; S. Soosairaj 7826; RHT!

Description

Annuals. Erect herbs to 15 cm with opposite branches. Stem pubescent (nonglandular), internodes 1.5-2.5 cm long. Leaves opposite, decussate, elliptic-oblanceolate, glabrous, base attenuate, apex acute, margin serrate, 18-22 × 4-5 mm, lateral nerves 3-4 pairs. Petiole 4-7 mm, winged. Stipule 2 × 0.75 mm, lanceolate, glabrous, apex acuminate, margin ciliate. Flowers axillary, 6-10 in fasciculate cymes, 1.5-2 mm across; pedicel 1-1.5 mm, pubescent, accrescent. Sepals 5, lanceolate, adnate at base, green at middle, pinkish red at both edges, pubescent abaxially, apex acuminate, margin ciliate, 2 × 0.75 mm. Petals 5, white, oblong, apex acute, mucronate, 2 × 1 mm. Stamens 10, two rows, filament glabrous, 1-1.5 mm long, dilated at base, anther 0.2 × 0.2 mm, basifixed. Pistil 1.5 mm long, ovary globose, glabrous, 1 × 1 mm, styles 5, pinkish, straight, 0.5 mm long, stigma subcapitate, papillose. Capsule globose, brownish. Seeds numerous, minute, oblong, yellowish brown, surface vesicular.

Acknowledgements

The authors are thankful to The Head, Southern Regional Centre, Botanical Survey of India, Coimbatore and The Director, Rapinat Herbarium, Tiruchirappalli for granting permission to access the herbarium deposits and the library. Drs Gregory John Leach (Northern Territory Herbarium, Palmerston) and Thierry Deroin (Muséum national d’Histoire naturelle) are also thanked for their comments on a previous version of the article.

Fig. 1. — Location map of study area and collection sites of Bergia ‌cuddalorensis ‌S. Soosairaj ‌sp. nov.,
Fig. 2. — Bergia ‌cuddalorensis ‌S. Soosairaj ‌sp. nov.,: A, habit; B, flower; C, stipule; D, sepal; E, petal; F, stamen; G, pistil. Scale bars: A, 5 mm; B, 1 mm; C, D, E, F, G, 0.4 mm. Drawing by Joseph Lincy.
Fig. 3. — Bergia ‌cuddalorensis ‌S. Soosairaj ‌sp. nov.,: A, habit; B, C, flower; D, sepal; E, fruit; F, fruit dehiscence. Scale bars: A, 4 mm; B, C, 0.3 mm; D, 0.2 mm; E, 2 mm; F, 0.4 mm. Photos by S. Soosairaj.
Table 1. — Distinct features of Bergia ‌cuddalorensis ‌S. Soosairaj ‌sp. nov., and its allied species.B. ‌cuddalorensisB. ‌suffruticosaB. ‌ammannioidesHabitErect herb, nonaromaticShrubs, aromaticErect herb, nonaromaticLeavesPetiolate, winged, glabrousSessile, densely glandular pubescentPetiolate, glandular pubescentStipuleGlabrousPubescentPubescentFlowers6-10 per node2-8 per nodec. 30 per nodeSepalsLanceolate, apex acuminate, glabrous, margin ciliate, pinkish redOvate, oblong, apex acute, glandular pubescent, margin hyaline.Lanceolate to ovate, apex acute, glandular pubescent, margin entirePetalsOblong, apex acute, mucronateObovate-oblong, apex obtuseElliptic to oblong, apex obtuseAnther0.2 × 0.2 mm0.5 × 0.3 mm0.3 × 0.3 mmOvaryGloboseOvoidSubgloboseCapsuleGloboseOvoidSubgloboseSeedOblong, surface vesicularOblong to ellipsoid, smoothOblong, surface reticulate
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