Didymocarpus moellerii A.Joe, Hareesh & M.Sabu, 2016

Joe, Alfred, Hareesh, Vadakkoot Sankaran, Prashob, Pulpara & Sabu, Mamiyil, 2016, Didymocarpus moellerii (Gesneriaceae): a new species from northeastern India, Phytotaxa 266 (1), pp. 57-60 : 57-59

Didymocarpus moellerii A.Joe, Hareesh & M.Sabu sp. nov. ( Figure 1 )

Didymocarpus moellerii is similar to D. glandulosus , but differs from the latter in having symmetric leaves with cordate bases; glabrous purple peduncle and pedicel; orbicular bracts; corolla funnelform, orange-red (throat with white striations); corolla tube 2–2.5 cm long, tubular, dilated and slightly ventricose towards the throat; ovary apex bulged and cupular disc. Didymocarpus moellerii is also similar to D. tonghaiensis , but differs from it in having glabrous peduncle, orbicular bracts, puberulent anthers and glabrous ovary.

Type:— INDIA. Arunachal Pradesh: Lohit District, Hayuliang road, near Tohangam View Point, 27º54 ′ 58.8 ″ N 096º19 ′ 55.0 ″ E, 1201 m, 8 July 2015, A.Joe & V. S.Hareesh 121948 (holotype CALI!, isotypes CALI!, CAL!).

Lithophytic herbs, stems 2.5–7 cm long, densely puberulent. Leaves 8–12, opposite; petiole 1–5.8 cm long, puberulent; lamina 2.2–10.5 × 2.5–9 cm, orbicular or ovate, thin when dry, adaxially densely puberulent, green, abaxially puberulent, pale green, apex acute or obtuse or rounded, base cordate or with shallow or deep basal sinus, margin serrate, veins 4–8 on each side, puberulent, prominent. Inflorescence axillary or pseudo-terminal (with the last pair of leaves greatly reduced), 15–15.5 cm long, 5–30 flowered; peduncle slender, 9–12 cm long, glabrous, purple, terete. Bracts 2, 0.3–0.4 × 0.3–0.4 cm, orbicular, persistent, glabrous, purple, margin entire. Pedicel 0.3–3.5 cm long, terete, glabrous, purple. Calyx actinomorphic, free from base, lobes 5, 2–4 × 0.8–1.5 mm, linear-oblong, apex sub-acute, purple, glabrous, margin entire, free from base. Corolla funnelform, 3–3.6 cm long, glabrous, orange red (throat with white striations), corolla tube 2–2.5 cm long, tubular, glabrous, dilated and slightly ventricose towards the throat; corolla bi-lipped, aestivation quincuncial, upper lip 2, 0.9–1.1 × 1.4–1.5 cm, lower lip 3, 1.7–1.8 × 1.4–1.5 cm; lobes broadly arrowheaded with obtuse apex, glabrous, orange-red. Stamens 2, 6–7 mm long, adnate to base of corolla lobe; filament 5–6 mm long, white, base glabrous, with glandular hairs at apex immediately below anther; anther 2–3 mm long, creamy, puberulent. Staminodes 2, 1.4–1.5 mm long, white. Disc cupular, 1.5–1.9 × 0.7–0.8 mm, apex unequal with undulate margins. Pistil 2.2–2.4 cm long; ovary 2–2.2 cm long, glabrous, base cream, with purple tinge towards stigma and apex green, bulbous just below stigma; stigma 1, 0.1–0.2 mm long, flap-like or circular, undivided, green, apex hairy. Capsule 4–4.5 cm long, linear, glabrous.

Taxonomic affinities: — Didymocarpus moellerii is morphologically similar to D.tonghaiensis and D.glandulosus , but differs in several aspects such as glabrous peduncle, orbicular purple bracts, puberulent anthers, orange-red corolla with white stripes at the throat, bulged ovary apex and cup-like disc ( Table 1).

Distribution, habitat and phenology:— Didymocarpus moellerii is an endemic spcies from India, found on moist rock faces near Tohangam View Point, near Tezu, Lohit District (Arunachal Pradesh). It grows in open places attached to rocks at an elevation of 1200 m. It flowers and fruits from June to September.

Etymology:— This species is named after Michael Möller, Royal Botanic Garden Edinburgh, for his great contribution to the knowledge of Gesneriaceae .

Figures

FIGURE 1. Didymocarpus moellerii A.Joe, Hareesh & M.Sabu. A. habitat; B. plants with flowers and dehiscent fruits; C. inflorescence (abaxial view); D. inflorescence (adaxial view); E. single flower; F. opened corolla showing stamens; G. pistil with calyx and cupular disc; H. stamen; I. cupular disc. Photos by Alfred Joe.