Ophiorrhiza caudata C.E.C.Fisch., Bull. Misc. Inform. Kew 1938: 125

Ophiorrhiza caudata C.E.C.Fisch., Bull. Misc. Inform. Kew 1938: 125 View in CoL . 1938; Deb & Mondal, Bull. Bot. Surv. India 39: 34. 1997. Type: INDIA, Kerala, Travancore High Range, Kalaar [‘Kallar’], May 1937, E. Barnes 1560 (holo K [ K0000174141 digital image!]). Fig. 2 View Fig

Herbs, 40–80 cm tall; stem erect, branching, terete at base, glabrous. Leaves elliptic-lanceolate, 9.5–13 × 2.5–3.5 cm, caudate-acuminate at apex, acuminate at base, glabrous; lateral nerve pairs 8–10; petioles 0.7–2.5 cm long, glabrous; stipules persistent, linear to lanceolate, 2.79–4.2 × 1.6–2.6 mm, margins entire, glabrous. Cymes terminal, capitate, 1–2 cm across, glabrous; peduncles 4–5.5 cm long, slender, glabrous. Flowers heterostylous, 11–11.5 mm long; bracts ovate to lanceolate, with a distinct midrib, 8.3–8.42 × 2–2.2 mm, glabrous; bracteoles ovate to lanceolate, with a distinct midrib, 6.8–7 × 2–2.1 mm, glabrous; pedicels 0.9–1.1 mm long, glabrous. Hypanthium obovoid, 0.9–1.3 × 0.9–1.6 mm, glabrous. Calyx lobes ovate-lanceolate, 0.75–1.1 × 0.7–0.75 mm, acute, glabrous. Corolla campanulate; tube 7.5–8.6 mm long, glabrous outside with a villous ring at middle of tube inside; lobes ovate, 2.4–3.2 × 2.14–2.29 mm, acute. Stamens adnate to middle of corolla tube, inserted; filaments 0.3–0.35 mm long in long-styled flower and 3.3–3.4 mm long in short-styled flower, glabrous; anther oblong, 1.2– 1.3 × 0.4–0.46 mm in long-styled flowers, 1.43–1.55 × 0.42–0.44 mm in short-styled flowers, oblong. Pollen grains sub-oblate, small, isopolar, monad, angular in polar outline, polar axis (P) × equatorial axis (E) = 19–20 × 23.5–24 µm, tricolporate; colpi 15–16 × 4–5 µm, elongated colpi with acute end; ora circular, 4.5–4.7 µm in diam.; microreticulate; surface lumen 0.6–1.1 µm diam. Ovary obovoid, 0.86–1 × 0.85–0.9 mm; styles 5.1–5.3 mm long in long-styled flowers and 0.9–1 mm long in short-styled flowers, glabrous; stigma bilobed, 1.12–1.2 × 0.86–0.87 mm and rounded in long-styled flowers, 1.9–2.1 × 0.68–0.71 mm and lanceolate in short-styled flowers, glabrous. Capsules obcordate, 3.2– 3.4 × 6.45–7.7 mm, glabrous, bilocular. Seeds 0.43– 0.46 × 0.3–0.32 mm, irregularly angled, glabrous, brown.

Flowering & fruiting: Flowering from May to October and fruiting from June to December.

Specimens examined: INDIA, Kerala, Idukki district, Kallar Valley , 700–800 m, N 10°03’39.5”, E 76°57’27.3”, 12.01.2021, Akhilesh S. V GoogleMaps . Nair 10235 ( KUBH) . Kerala, Idukki district, Kallar valley , 21.02.2012, E. S . Santhosh Kumar & P. E . Roy 70440 ( TBGT) .

Distribution: Endemic to Western Ghats of Kerala.

Habitat: In moist, shady places of the evergreen forests and also along the banks of streams or rivulets, between 700–800 m altitude, along with Ophiorrhiza barberi , O. barnesii ., Argostemma courtallense (all Rubiaceae ), Sonerila wallichii ( Melastomataceae ).

Conservation status: During our field trip in 2021 in Kallar Valley in Idukki district of Kerala, we had the opportunity to observe two populations of O. caudata , each consisting of fewer than 100 mature individuals. The species occurs in moist and cool shady environment along rock cuttings near streams. Since the locality is outside a protected area, it is facing serious threat due to anthropogenic activities and roadside cleaning acitivities, etc. Considering the specific location and the small size of the population, it is likely that their numbers will further decline. Based on the IUCN Red List Criteria ( IUCN, 2012, 2022), O. caudata is assessed here as Critically Endangered (CR), B2a,b (iii,v).