Torenia hookeri (C.B.Clarke ex Hook.f.) A.Pal & M.Chowdhury

Pal, Aaratrik & Chowdhury, Monoranjan, 2022, Torenia hookeri, a new combination in Asian Linderniaceae and first record of T. godefroyi in the Himalayan hotspot, Phytotaxa 549 (2), pp. 230-234 : 230-231

Torenia hookeri (C.B.Clarke ex Hook.f.) A.Pal & M.Chowdhury comb. nov.

≡ Vandellia hookeri C.B.Clarke ex Hooker (1884: 280) . ≡ Lindernia hookeri (C. B.Clarke ex Hook.f.) Wettst. in Engler & Prantl (1891: 80). ≡ Pyxidaria hookeri (C.B.Clarke ex Hook.f.) Kuntze (1891: 464) .

Lectotype:— INDIA. Khasia: below Pomrang , cultivated field, 2–4000 ft., 2 October 1850, J.D. Hooker & T.Thomson 10 ( K [ 000859668 !]) . ( Fig. 1 )

Annual herbs up to 35 cm tall. Stem green (or reddish), erect or ascending, hispid, 4-angular. Leaves shortly petioled or sessile, petiole up to 5 mm, lamina ovate-lanceolate, 17–28 × 7–15 mm, sometimes narrowed in middle, pinnately veined, acute, cuneate to sub-cordate, serrate; serration 3–10 pairs, with bristles on apices. Pedicels axillary-solitary, racemes or subumbel-like at branch apices, 5–15 mm in flowers, 9–25 mm in fruits, quadrangular. Calyx green, distinctly 5-winged, densely ciliate, bi-lipped, upper lip 3-lobed, lower lip bi-lobed, 4–5 mm long in flowers, 6–7 mm long in fruits. Corolla ca. 8 mm long, purple or violet, tube whitish-yellow, bilabiate, upper lip emarginate, lower lip 3-lobed, lobes rounded, middle lobe shows a yellow spot surrounded by a whitish patch. Stamens 4, perfect, pale purple, united as pairs at theca; upper pair of filaments shorter, theca larger, ca. 1.5 mm long; lower pairs of filaments longer, ca. 2.5 mm long, with tooth-like purple appendage, ca. 0.3 mm, theca minute. Ovary green, linear-oblong, ca. 2 mm long, slightly bend at apical half, glabrous expect scabrid apical lateral half. Disk greenish yellow, ca. 0.3 mm, covering ca. 1/6th of the ovary from base. Fruit completely enclosed by calyx. Seeds irregular in shape with rounded pits on surface (bothrospermous).

Notes:— T. hookeri can be easily distinguished from other Torenia by the size of the densely hairy calyx and purple or violet corolla with a yellow spot surrounded by a whitish patch on the lower lip.

Phenology:— Flowers and fruits recorded in October–November.

Distribution, habitat and ecology:— The species is recorded from China, India (Bihar, Jharkhand, Madhya Pradesh, Meghalaya (Khasi Hills), West Bengal), Myanmar, Nepal, Thailand, and Vietnam. The authors observed it in open lands of moist habitats with several marshy herbs and grasses. It’s also recorded to be grown on cultivated fields.

Additional specimens examined:— INDIA. Khasia: below Pomrang, cultivated field, 2–4000 ft., 2 October 1850, J.D. Hooker & T. Thomson 10 (BM, CAL, K, P); West Bengal: Darjeeling district, Siliguri, Raja Rammohunpur, 26°42′38.50″N, 88°21′12.60″E, 06 Nov 2020, LIND 20201106 (NBU); Jharkhand: Chotanagpur, Parasnath, 17 November 1874, C. B. Clarke 24749C (CAL); Madhya Pradesh: Kanha National Park, November 1970, R.M. Singhal (DD). CHINA. Yunnan, 19 July 1898 (P). NEPAL. Pokhara, 3000 ft., 12 August 1954, Stainton, Sykes & Williams 6767 (E); Western Development Region: Gandaki zone, Gorkha district, 28°2′36″N, 84°48′40″E, 860 m, 23 July 2008, Ekeda et al. 20811019 (E). MYANMAR. Pegu, Yomah, Eng Forests, S. Kurz 301 (CAL); Yomah, E. and W. slopes, 29 December 1870, S. Kurz 2300 (CAL); Pegu, 29 December 1871, S. Kurz 2300 (CAL); Pegu, 26 December 1871, S. Kurz 2305 (CAL). VIETNAM. Cochinchina, Thorel 1587 (P); Tonkin, 04 February 1908 (P).

Figures

FIGURE 1. Torenia hookeri. A. habit; B. lateral view & C. dorsal view calyx; D. section of flower; E. ovary with disc. Each division = 1 mm. Prepared by A. Pal.