Solanum pulneyensis Soosairaj, 2021

Soosairaj, Sebastian, Raja, Prakasam, Balaguru, Balakrishnan & Tagore, Johny Kumar, 2021, Solanum pulneyensis Soosairaj, sp. nov. (Solanaceae) from Palani Hills National Park of Tamil Nadu, India, Adansonia (3) 43 (21), pp. 235-240 : 236-238

Solanum pulneyensis Soosairaj , sp. nov.

( Figs 1 ; 2 )

TYPUS. — India. Tamil Nadu, Dindigul district, Palani Hills National Park, Thonimalai , (10°22’37.95”N, 77°46’41.99”E), c. 1300 m, 29. I.2018. S. Soosairaj 2514 (holo-, RHT!; iso-, MH!).

DIAGNOSIS. — This species differs from other Solanum species by subcapsular fruits that are entirely enclosed by calyx. It has supra axillary cyme inflorescence with 2-3 flowers. This species also has distinctive features such as obtuse leaf apex, unarmed petiole and pedicel, simple stigma and glabrous anther.

HABITAT AND PHENOLOGY. — Solanum pulneyensis Soosairaj , sp. nov. was found growing in savanna forest in the Western Ghats of Palani Hills National Park, on a slope at 1300 m elevation amidst tall grasses like Cymbopogon citratus (DC.) Stapf. The vegetation type has been described as sub-tropical hill savanna (8A/DS1) which is interrupted with patches of southern hill top wet evergreen forests ( Champion & Seth 1968). The new species was found associated with Breynia retusa (Dennst.) Alston , Peperomia blanda (Jacq.) Kunth , Kalanchoe bhidei Cooke , Hedyotis swertioides Hook. f., Pogostemon mollis Benth. , Desmodium parvifolium DC. , Kleinia grandiflora (DC.) N. Rani , Smithia hirsuta Dalzell , Arundinella ciliata (Roxb.) Nees ex Miq. , Eragrostis deccanensis Bor. and Polygala rosmarinifolia Wight & Arn. The species is found growing in steep slope and soil is shallow with exposed rocks. Flowering occurs in January-March, and fruiting from February and March.

DISTRIBUTION. — Solanum pulneyensis Soosairaj , sp. nov. is known only from the Thonimalai, Palani Hills National Park, Dindigul district from Tamil Nadu, India.

ETYMOLOGY. — The specific epithet is chosen to represent the Palani hills, the collection locality which is a part of Western Ghats of India.

CONSERVATION STATUS. — The population of this species was noted at two locations at a close proximity observed to be populated with about 15-20 individuals. Based on the field observations made periodically, the conservation status of the species has been evaluated following the latest IUCN Red List Criteria (Version 3.1; IUCN 2012). The species qualifies for Critically Endangered under criteria B2, C2 and D. Criterion B1 cannot be estimated as the EOO required to predict is at least 2 locations ( Fig. 3 ).

Criterion B2: This species is found only at the Thonimalai (subcriterion a). The AOO measured at 2 km 2 grid size for Solanum pulneyensis Soosairaj , sp. nov. is 4 km 2. A continuing decline of population is inferred (subcriterion b) in terms of quality of habitats such as the construction of estate and tea plantations. As this estimate is less than 10 km 2, the species qualifies for Critically Endangered category.

Criterion C2: A continuing decline of population is inferred in terms of quality of habitats as the establishment of estate and tea plantations push this species to extreme. The number of mature individuals in the population noted was about 15-20 individuals.

Criterion D: Only ten to fifteen individuals in total were documented during the study period which is much lower than the threshold level of fifty mature individuals and makes the species qualify for Critically Endangered category criterion.

Though this species could be considered as Data Deficient (DD) due to its distribution, we could anticipate that the uncertainty on the conservation of the habitats which are favorable for the growth of Solanum pulneyensis Soosairaj , sp. nov. shall be assessed as Critically Endangered criteria CR[B2ab(iii); C2a(i); D].

DESCRIPTION

Armed, undershrub, 50-70 cm tall, stellate tomentose throughout. Stem stellate tomentose, prickled, prickles straight, 1-1.5 mm, yellow. Leaves simple, alternate, oblong-ovate, 3-6.5 × 2-4 cm, base truncate, oblique, margin undulate, stellate tomentose on both the surfaces, apex obtuse, midrib with 1 or 2 prickles below, lateral nerves 3-4 pairs, without prickles; petiole 8-23 mm, prickled. Inflorescence a cyme, supra axillary, 2-3 flowered, peduncle 5-6 mm long. Flowers 20-23 mm across, pedicel up to 18 mm, not prickled; Calyx cupular, rotate, 9-10 mm, densely stellate tomentose without, glabrous within, lobes 5, lanceolate with prominent midnerves, 5-6 mm, apex acuminate; Corolla rotate, 5 lobed, pale purple, lobes orbicular, 4-5 mm, undulate, stellate tomentose without, glabrous inside, midnerve yellowish from the base; Stamens 5, filaments 1-2 mm, glabrous, anthers unequal, 3 long, 7-8 mm, falcate, 2 short, 5-6 mm, lanceolate, glabrous, yellow, poricidal. Pistil 12 mm; ovary ovoid, 1-1.5 mm, style 11-12 mm long, capillary, glabrous, curved; stigma simple. Fruit subcapsular, globose, 8-10 mm across, pale green with white patches, fruiting calyx accrescent, 13-14 mm, lobes 10-11 mm, stellately tomentose, not prickled. Seed rhomboid, 3.5× 3 mm, pale brown, alveolate, margin bulged.

AFFINITIES

Solanum pulneyensis Soosairaj , sp. nov. is a distinct species since it has a subcapsular fruit. It resembles with S. wightii Nees in having accrescent fruit calyx that covers the fruit completely but differs in having subcapsular fruit, obtuse leaf apex, glabrous anther, calyx and petiole without prickles ( Table 1 ). It is also similar to S. cordatum in having similar features like oblong-ovate leaves, 2-3 flowered cymes but differs in having subcapsular fruit that dehisces irregularly at apex and fruit that is pale green with white patches. Although most of the Solanum species have berry as common fruit type, Symon (1979, 1981) reports subcapsular fruit in Solanum rostratum Dunal , a widespread weed in his revision of Australian Solanum species.

Figures

FIG. 1. — Solanum pulneyensis Soosairaj, sp. nov.: A, habit (a twig); B, calyx; C, corolla (with stamens); D, corolla (without); E, F, anthers; G, pistil; H, fruit (with calyx); I, fruit; J, seed; A-J, drawn from the type Soosairaj 2514. Scale bars: A, 1 cm; B, H, 2.5 mm; C, D, 5 mm; E-G, 2 mm; I, 8 mm; J, 4 mm.

FIG. 2. — Solanum pulneyensis Soosairaj, sp. nov., a twig.

FIG. 3. — Distribution map of Solanum pulneyensisSoosairaj,sp.nov.,generated using GeoCAT.