Ophiorrhiza medogensis H.Li var. shiyomiense Hareesh & M.Sabu

Hareesh, Vadakkoot Sankaran & Sabu, Mamiyil, 2022, Taxonomic studies on Indian Ophiorrhiza L. (Rubiaceae): with a new variety, new distributional record of O. medogensis H. Li for India and the identity of O. recurvipetala Bhuyan, Baruah & Mehmud, Adansonia (3) 44 (5), pp. 29-36 : 30

Ophiorrhiza medogensis H.Li var. shiyomiense Hareesh & M.Sabu , var. nov.

( Fig. 1 )

The new taxon shows similarities with O. medogensis H.Li , but differs from the latter in having densely villose corolla with non-inflated throat and pale yellow with green tinge towards the lobes.

TYPE. — India. Arunachal Pradesh, Shi-Yomi district, near Sikko Dido Water fall, 18.IX.2019, M. Sabu & V.S. Hareesh 158760 (holo-, MBGH! ; iso-, CAL!, MBGH!)

PHENOLOGY. — Flowering started in August.

ETYMOLOGY. — The varietal epithet is named after the type locality of the taxon, Shi-Yomi district, Arunachal Pradesh.

HABITAT, DISTRIBUTION AND CONSERVATION STATUS. — The new species is known only from type locality, near Siko Dido Water fall towards Mechuka, Shi-Yomi District of Arunachal Pradesh. The plants were growing in the moist sloppy areas at an altitude varying from 1100 to 1200 m a.s.l. During our expedition, we observed three populations with more than 50 mature individuals. It is growing in association with Impatiens paramjitiana Gogoi & Borah , I. arguta Hook.fil. & Thomson , Pilea sp. According to the present field observation data, the new species is tentatively classified as Data Deficient (DD) ( IUCN 2017).

DESCRIPTION

Erect/decumbent herbs, 20-50 cm tall; stem branched, woody at base, terete, green to pinkish-green, pubescent; internodes 2-13 cm long.Stipules c. 1 cm long, with2-4 subulate to filiform lobes, pubescent, persistent. Petiole 1-2.5 cm long, slender, pale green or rarely pale pink with densely pink pubescence. Leaf blades 3.5-9 × 1.75-4 cm, elliptic or ovate to ovate-lanceolate, acute or acuminate at apex, rounded to subcordate at base; margin entire, undulate, ciliate; adaxially green, rarely with yellow coloration, sparsely pubescent to pubescent, abaxially pale green, pubescent; secondary veins 9-14 on either sides. Inflorescence terminal corymb, 2-3 cm in diameter; peduncle c. 3 mm long, terete, densely villose; bract and bracteoles similar, lanceolate, 10-13 × c. 1 mm, green or rarely with purplish tinge, pubescent, prominently nerved, persistent. Pedicels 2-2.5 mm long, pale green, densely villose. Flowers 20-24 mm long. Hypanthium 1.5-2 × 2-2.5 mm, obovoid, pale green with dense pink villose hairs. Calyx lobes filiform, unequal in length, 3.5-6 × c. 0.5 mm, acute at apex, pale green to green, pubescent. Corolla infundibuliform, 18-20 mm long, pale yellow with green tinge towards the lobes, densely villose; lobes c. 2 × 1.5 mm, ovate, acute at apex, minutely keeled on back. Long-styled flowers: internally with a villous ring just above the middle of the corolla tube, followed by dense long pubescence towards the throat and small hairs to the lobes and glabrous below; stamens inserted in the middle of corolla tube below the villous ring; filaments 0.60-0.75 mm long; anthers oblonglinear 1.75-1.9 mm long, white or pale yellow; style filiform, 10-11 mm long, ciliate; stigma c. 2 mm long, linear to oblanceolate, pale yellow, glabrous to papillose.Short-styled flowers: internally with a villous ring just below the corolla throat, followed by dense short pubescence towards the lobes and dense long pubescence towards the base of corolla followed by 3 mm glabrous portion; stamens inserted just above the middle of corolla tube; filaments 1.5-1.75 mm long; anthers oblong-linear 1.75-2 mm long, white or pale yellow; style filiform, 4-4.5 mm long, ciliate; stigma 2-2.5 mm long, oblanceolate, pale yellow, glabrous to papillose. Ovary 2-celled, ovules numerous; disc 0.5-0.75 mm high. Capsule obcordate, 5-8 × 5-11 mm, pale green, pubescent; seeds angular, pale brown.

Figures

FIG. 1. — Ophiorrhiza medogensis H.Li var.shiyomiense Hareesh & M.Sabu, var.nov.:A, habit; B, a twig with inflorescence;C, inflorescence side view;D, inflorescence (short-styled);E, inflorescence (long-styled);F, G, floral parts of short-styled flower:F, split-opened corolla showing stamens;G, calyx with style and stigma; H, I, floral parts of long-styled flower: H, corolla showing stamens; I, calyx with style and stigma; J, infructescence. Scale bars: 5 mm. Photos by V.S. Hareesh.