Argyreia lawii C.B.Clarke

B., Sadasivaiah, P., Rahul, P., Bharath Simha Yadav & Prasad, K., 2024, Extended distribution of endemic species Argyreia lawii (Convolvulaceae) from the Western Ghats to the Eastern Ghats ecoregion, India, Rheedea 34 (5), pp. 516-520 : 517-519

Argyreia lawii C.B.Clarke in Hook.f., Fl. Brit. India 4: 190. 1883; T.Cooke, Fl. Bombay 2: 257.

1905; Talbot, Forest Fl. Bombay 2: 287. 1911;

Gamble, Fl. Madras 2: 908. 1923; B.D.Sharma et al., Fl. Karnataka: analysis 179. 1984; Venkanna &

Das in N.P. Singh et al., Fl. Maharashtra, Dicot. 2:

445. 2001; P. Singh et al., Endemic Vasc. Pl. India

144. 2015; Shalini et al., Indian J. Forest. 41(3):

265. 2018; Lawand et al., J. Threat. Taxa 11(14):

14918. 2019; Rajeswari & Nisha, J. Threat. Taxa

15(7): 23627. 2023. Lectotype (designated by

Lawand & Shimpale, 2017): INDIA, Karnataka, Baba Budan Hills, s.d., Law 28 (K [K000830722]

image!). Fig. 1

Perennial climbers. Stems terete, herbaceous towards apex and basal semi-woody, green, strigose-villous, white silky hairy. Leaves simple, alternate; petioles terete, 1.5–3 cm long, strigose-villous, channelled above; lamina ovate or elliptic-ovate, 4.5–13.5 × 2–9 cm, base truncate to rounded, margins entire, apex acute and apiculate, sparsely hirsute above, densely hirsute below, dark green above, white below, secondary nerves 6–11 pair, veins strongly impressed below. Inflorescence a compact cyme, axillary, 3–5-flowered, dichotomously branched with one central flower or not; peduncle longer than petiole, terete, 4.5–8 cm long, hirsute to strigose-villous. Flowers subsessile; bracts 3, subequal; outer bract lanceolate or oblong-lanceolate, 1.5–2 × 0.5 cm, margins entire, apex acute or mucronate, white hairy, faintly three nerved, wider than the inner ones; inner bracts linear or linear-lanceolate, 1.4–1.8 × 0.2 cm, margins entire and ciliate, apex acute or mucronate, white hairy, faintly three nerved. Sepals 5, subequal; outer two ovate, c. 8 × c. 4 mm, apex acute, hirsute outside, glabrous inside, purple margined; inner three ovate, c. 7 × c. 5 mm, apex acute, hirsute outside, glabrous inside, hyaline margines, base with prominent purple tinge. Corolla deep pink or pink-purple, infundibuliform, 6–7 cm long, 5–5.5 across, hairy outer on midpetaline bands, corolla lobes twisted in bud. Stamens 5, inserted in corolla tube, unequal in length, filaments pink, dilated and glandular hairy at base; short filaments 3, 0.6–0.8 cm long; long filaments 2, 1.3–1.5 cm long; anthers basifixed, arrow shaped, 3–4 mm long, pale pink. Ovary conical, pale green, 1–2 mm diameter, encircled by angular disk; style 2.5 cm long, white, glabrous; stigma biglobose, papillate, pink. Fruits not seen.

Flowering & fruiting: Flowering from September to October; fruiting not observed.

Habitat & ecology: Rarely found in dry deciduous forests under shady condition, on red soils with humus, at an altitude of 700– 750 m. It grows in association with Argyreia sericea Dalzell & A. Gibson , Apluda mutica L., Cynoglossum zeylanicum (Sw. ex Lehm.) Thunb. ex Brand, Grewia rothii DC. , Rhynchosia rothii Benth. ex Aitch. , Phanera vahlii (Wight & Arn.) Benth. , Triumfetta rhomboidea Jacq. , Heteropogon contortus (L.) P. Beauv. ex Roem. & Schult., Phoenix loureiroi Kunth , Dioscorea bulbifera L., Oplismenus compositus (L.) P.Beauv. etc. Generally, climbing on Phanera vahlii and other adjacent species.

Distribution: Endemic to Peninsular India. Western Ghats: Karnataka (Konkan Province & Baba Budan Hills), Kerala (Thavalam, Palakkad District), Maharashtra (Bhudargad Fort & Patgaon, Kolhapur District), and Tamil Nadu (Nilgiris District, Coonoor Ghat) and Eastern Ghats (Nagarkurnool District, Telangana – present report).

Specimens examined: INDIA, Telangana, Nagarkurnool District, Way to Srisailam,

10.10.2024, B . Sadasivaiah, P. Bharath, P. Rahul & K.

Prasad 5088 (TBGH! & BSID!).

Conservation status: Argyreia lawii is primarily known from the Western Ghats, but the present collection from the Eastern Ghats of peninsular India highlights its status as a narrowly endemic species in this region. At the current collection site, the species has a restricted distribution, with approximately 20 individuals observed in the Achampet Forest Division (on the route to Srisailam) in Nagarkurnool District, Telangana. The species’ habitat is currently under significant threat due to seasonal and anthropogenic forest fires, as well as a major biological threat from an unidentified larvae. Based on ‘Extent of Occurrence’ (Criterion B1: EOO < 100 km 2) and ‘Area of Occupancy (Criterion B2: AOO < 10 km 2), together with the number of locations – 1 (subcriterion ‘a’) and the projected decline in area, extent and/or quality of habitat (subcriterion ‘b(iii)’), A. lawii is tentatively assessed here as ‘Critically Endangered [CR B1 B2 a, b(iii)]’ ( IUCN, 2024) in the Eastern Ghats ecoregion. Further exploration across its entire distribution range is needed to ascertain its actual status.

Note: Fruit set was not observed in this species, as the stamens were predominantly predated upon by larvae of an unknown species. Nearly all the stamens were consumed by the larvae, while the pistil remained unaffected. A distinctive feature of this species is the prominent purple tinge at the base of each sepal, a characteristic not observed in any other species of the genus. This unique trait serves as a key distinguishing feature for this species.