Ophiorrhiza medogensis H.Li

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 : 32

Ophiorrhiza medogensis H.Li

( Fig. 2 )

Acta Phytotaxonomica Sinica 18 (1): 116 ( Li 1980).

TYPE SPECIMEN. — Tibet. Guangxi, Xizang, Medog Xian , in silvis, Quinghai-Xizang , 1720 m, 10.IX.1974, Complex Expeditio 74-5072 (holo-, KUN ; iso-, PE [ PE00808294 , PE00808295 ]!) .

SPECIMEN DATA. — India. Arunachal Pradesh, Dibang Valley district, Near Mayodia , c. 1700 m, 22.IX.2019, M. Sabu & V.S. Hareesh 158780 ( CALI, MBGH) .

HABITAT, DISTRIBUTION AND CONSERVATION STATUS. — Ophiorrhiza medogensis was known only from Xizang of Medog of China/Tibet on slopes of the broad leaved forest at an altitude around 1700 m. In India, it is growing in the sloppy areas near the Mayodia, Dibang Valley district and near Siko Dido Water fall, Shi-Yomi District of Arunachal Pradesh, NE India. The plants were growing in the moist sloppy areas at an altitude varying from 1100 to 1700 m a.s.l. in association with Amomum sericeum Roxb. , Henckelia pumila (D.Don) A.Dietr. , Elatostemma sp. , Impatiens arguta Hook.f. & Thomson , Pilea sp. At present, O. medogensis perceives no serious threat to its existence in the field. During our expedition, we observed three populations with more than 50 mature individuals. According to the present field observation data, the new species is tentatively classified as Data Deficient (DD) ( IUCN 2017).

DESCRIPTION

Erect/decumbent herbs, 20-60 cm tall; stem branched, woody at base, terete, green to brownish-green, densely villose; internodes 2-10 cm long. Stipules 3-6 long subulate or linear with 1-3 filiform lobes, pubescent, persistent. Petiole 1-2 cm long, slender, pale green with densely pink pubescence. Leaf blades 3-11.5 × 1. 5-3.5 cm, elliptic or ovate to ovate-lanceolate, acute or acuminate at apex, cuneate or rounded to subcordate at base; margin entire, undulate, ciliate; adaxially green, abaxially pale green, densely pubescent on both surfaces; secondary veins 7-16on either sides.Inflorescence terminal corymb, 2.5-3.5 cm in diameter; peduncle 3-5 mm long, terete, densely villose; bract and bracteoles similar, lanceolate, 6-10 × c. 1 mm, green pubescent, prominently nerved, persistent. Pedicels 2-2.5 mm long, pale green, densely pink villose. Flowers 22-25 mm long. Hypanthium 1.75-2 × 2.5-3 mm, obovoid, pale pink with dense pink villose hairs.Calyx lobes filiform, unequal in length, 4-7 × c. 0. 5 mm, acute at apex, pale pink, pubescent. Corolla infundibuliform, 20-23 mm long, white with pale pink tinge from base towards the middle of corolla tube, puberulent from the base towards the middle and pubescent on the ridges of the corolla lobes externally; lobes c. 3.5-4 × 3.5-4 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 0.50-0.75 mm long; anthers oblong-linear 2.75-3 mm long, white or pale yellow; style filiform, 12-13 mm long, ciliate; stigma c. 3.5 mm long, linear to oblanceolate, white pale yellow, glabrous. 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 tube; stamens inserted just above the middle of corolla tube; filaments 1.75-2 mm long; anthers oblong-linear 2.75-3 mm long, white or pale yellow; style filiform, 5-5.5 mm long, ciliate; stigma 2.5-3 mm long, oblanceolate, pale yellow, glabrous to papillose. Ovary 2-celled, ovules numerous; disc 0.75-1 mm high. Capsule obcordate, 5-6 × 7-12 mm, pale green, pubescent; seeds angular, pale brown.Flowering August-October, Fruiting October-December.

NOTES

Ophiorrhiza medogensis was considered as a Himalayan endemic species distributed in Tibet/China,which shows close resemblances with Ophiorrhiza subcapitata Wall.ex Hook.f. , but differs in having filiform stipules with 2/3 lobes, linear ciliate bracts and long ciliate calyx lobes.It is a large white flowered species with densely pubescent inflorescence, with a wide range of variations in the lamina hairy nature. The present collection from Mayodia of Arunachal Pradesh of India is the extended distributional record of this taxon to the flora of India.While describing O. medogensis , it was mentioned that the inflorescence has only long styled flowers and long calyx lobes.However,the collection from Arunachal Pradesh possesses both long-styled and short-styled flowers in a single population, which are mentioned in detail in the species description. In addition, it also shows variation in the size of the corolla lobe i.e. c. 2 mm less than the type material.

Figures

FIG. 2. — Ophiorrhiza medogensis H.Li: A, a twig with inflorescence (inset: part of inflorescence enlarged); B, inflorescence (long-styled); C, inflorescence (shortstyled); D, E, floral parts of long-styled flower: D, corolla showing stamens; E, calyx with style,stigma and bracts;F, G, floral parts of short-styled flower:F, splitopened corolla showing stamens; G, calyx with style and stigma. Scale bars: 5 mm. Photos by V.S. Hareesh.