Lepidagathis narasimhanii Gnanasek., A.F.J.King & Arisdason, 2023

Lepidagathis narasimhanii Gnanasek., A.F.J.King & Arisdason View in CoL , sp. nov. FiGS. 4–6 View FiG View FiG View FiG & 7c, G View FiG

Lepidagathis narasimhanii is morphologically similar to L. keralensis but differs in having the following characters: (i) Vegetative leaves lanceolate to lance-ovate, 9–22.5 × 1.6–6.5 mm, sparsely hirsute throughout ( vs. lance-ovate to oblong, 4–10 × 1.5–2 mm, glabrous); (ii) Inflorescence robust, 1.5–2 cm broad due to the spreading fertile bracts, with a maximum of 20 flowers ( vs. narrow, up to 1 cm broad due to appressed sterile bracts, with a maximum of 30 flowers); (iii) one or two flowers per node and more than half of the nodes (3–9 out of 6–12 nodes) bearing two flowers ( vs. always one flower per node); (iv) Sterile bracts present only in less than half of the nodes, narrowly ovate to elliptic, 8–14 × 2–5.5 mm ( vs. present in all the nodes, lance-ovate to narrowly elliptic, 7.4–8.5 × 1.6–2 mm); (v) Fertile bracts 9–14.5 × 2.5–5.2 mm, up to 7-veined ( vs. 7–9 × 1.7–2.6 mm, up to 5-veined); (vi) Bracteoles lanceolate to linear, 7–9 × 1.2–1.8 mm ( vs. narrowly elliptic, 4.8–6.6 × 1–1.4 mm); (vii) Corolla 14.5–17 mm long, magenta/dark purplish-red, crimson red at anthesis ( vs. 11.3–13.8 mm long, pink, purplish at anthesis; (viii) Capsules 5.3–7 mm long ( vs. 4.5–5.7 mm long).

Type: INDIA, Kerala, Kasaragod district, Seethangolli , N 12°35’31.0”, E 75°00’11.5”, 75 m, 29.12.2021, G. Gnanasekaran & A. F. J. King 12847 (holo CAL; iso MH, Madras Christian College Herbarium, Chennai) GoogleMaps .

Prostrate perennial herb with woody rootstock; stems spreading 1–2 m in diam., rooting at nodes, green to purplish when young, ash-coloured when old, well-branched, 4-angled; hirsute when young, glabrous when old; internodal distance 3–32 mm. Leaves sessile, opposite-decussate; vegetative leaves lanceolate to lance-ovate, 9–22.5 × 1.6–6.5 mm, base rounded or truncate, margins entire, apex acute with a minute spinose process, sparsely hirsute throughout; with 2–4 pairs of lateral veins; leaves of inflorescence bearing twig lance-ovate to elliptic, apex acute with a long-spinose apical process, tomentose throughout, otherwise same as vegetative leaves. Inflorescence a spike, raised at terminal of branches, 2–7 cm long, 1.5–2 cm broad (due to the spreading bracts), green to purplish-brown. Flowers up to 20, arranged in 4 ranks, very rarely in 2 ranks, 1 or 2 flowers per node and more than half of the nodes bear 2 flowers. Bracts: sterile bract 1 (present only in less than half of the nodes), narrowly ovate to elliptic, 8–14 × 2–5.5 mm, apex acute to acuminate with a spinose process, tomentose intermixed with glandular hairs throughout, 5–7-veined; fertile bract 1, narrowly ovate to elliptic, 9–14.5 × 2.5–5.2 mm, otherwise as sterile bracts. Bracteoles 2, lanceolate to linear, 7–9 × 1.2–2.2 mm, apex acuminate with a spinose process, tomentose intermixed with glandular hairs throughout, 3-veined. Calyx 5-lobed; lobes heteromorphic, apices acute to acuminate with a spinose process, tomentose intermixed with glandular hairs throughout; anticous lobes 2, unequal, lobes oblong to elliptic, 7.4–10.3 × 1.7–2.7 mm (large lobe) and 7.4–9.4 × 1.4–2 mm (small lobe), 3–5-veined, connate at base (a quarter to one-third of its total length, i.e., 2–3.7 mm long), overlapping; posticous lobe lance-ovate to ovate, elliptic, 9.5–12 × 2.6–6.2 mm, 5–7-veined; lateral lobes 2, lanceolate to linear-oblong, 6.5–9 × 1–2 mm. Corolla 14.5–17 mm long, magenta (dark purplish-red) throughout (crimson red at anthesis) with yellowish dots or patches on palate and purplish-brown horizontal striations only at membranous portion on either side of palate; tube 8–10.2 mm long, cylindrical below for 3.6–5.3 mm long, abruptly expanded above for 3.4–5 mm long, glabrous inside, retrorsely hirsute outside; upper lip arcuate, 3.3–4.6 × 4.8–6.7 mm, margins entire, minutely 2-lobed ( 0.5–1 mm long) at apex, each lobe 3-veined; lower lip 3-lobed, 5.7–7.3 mm long including lobes, glabrous; middle lobe broader than lateral lobes, suborbicular, 2.8–4 × 2.5–3.8 mm, apex entire or retuse, 3-veined; lateral lobes oblong, 2.5–3.6 × 2.2–3 mm, 3-veined. Stamens 4, didynamous; filaments purple to white, adnate at base of expanded corolla tube, glabrous; anticous filaments 3–5.4 mm long; posticous filaments 2.2– 3.7 mm long; anthers bithecous; thecae oblong-elliptic, divergent, 1.2–2 mm long, purple to white, sparsely hairy at base of suture and at connectives, longitudinally dehiscing. Pollen grains prolate, 33.7– 38.3 × 20.6–23.2 µm, tri-colporate, reticulate tectum more open in area adjacent to apertures. Ovary sub-globose, 1–1.6 × 1–1.3 mm, glabrous, 2-loculed; ovules 2 in each locule; nectary disk cupulate; style 7.5–9 mm long, bristled-glandular-hairy; stigma bi-lobed. Capsules ovoid in face view, 5.3–7 × 2.4–2.6 mm, glabrous; seed 2 (one fertile, one abortive), ovoid in face view, 2–3 × 1.6–2.3 mm, covered with short hygroscopic hairs.

Flowering & fruiting: Flowering from November to January; fruiting from January to April.

Habitat: On exposed rocky surface of low-elevation lateritic plateaus at elevations ranging from 50 to 120 m.

Distribution: India, endemic to Kerala.

Etymology: The species is named after Dr. D. Narasimhan, former Head of the Department of Botany, Madras Christian College (Autonomous), Chennai, for his outstanding contributions to plant taxonomy.

Specimens examined: INDIA, Kerala, Kannur district, Cheemeni, N 12°13’56.3”, E 75°13’59.9”, 117 m, 27.12.2021, G. Gnanasekaran & A. F. J. King 12835; Arippara, N 12°14’30.1”, E 75°16’48.5”, 117 m, 28.12.2021, G. Gnanasekaran & A. F. J. King 12836; Ibid., 06.12.2022, A. F. J. King & V. H. Ari 12978; Hosdurg, N 12°17’50.3”, E 75°09’40.4”, 52 m, 28.12.2021, G. Gnanasekaran & A. F. J. King 12840; Neeleshwar, N 12°16’18.2”, E 75°09’30.0”, 52 m, 28.12.2021, G. Gnanasekaran & A. F. J. King 12839; Veeremalai Kunnu, N 12°13’55.7”, E 75°09’24.3”, 49 m, 28.12.2021, G. Gnanasekaran & A. F. J. King 12838; Ibid., 06.12.2022, A. F. J. King & V. H. Ari 12979 (Madras Christian College Herbarium, Chennai). Kasaragod district , Seethangolli, N 12°35’31.0”, E 75°00’11.5”, 75 m, 15.10.2021, A. F. J. King & S. P. Nithya 12822; Ibid., 29.12.2021, G. Gnanasekaran & A. F. J. King 12848; Edanad, near Government ITI, N 12°36’33.3”, E 75°00’20.5”, 92 m, 29.12.2021, G. Gnanasekaran & A. F. J. King 12849; Manjeshwar, N 12°34’42.0”, E 74°59’25.1”, 53 m, 29.12.2021, G. Gnanasekaran & A. F. J. King 12844; Soorambial, N 12°35’44.6”, E 74°59’10.7”, 72 m, 29.12.2021, G. Gnanasekaran & A. F. J. King 12846 (Madras Christian College Herbarium, Chennai) GoogleMaps .

Conservation status: The estimated EOO and AOO for this species are 360.5 km 2 and 36 km 2, respectively. Even if it was collected from only nine different localities of Kannur and Kasaragod districts in Kerala, the species found growing continuously in different suitable habitats between the collected localities. Although this species is very common in the localities where it was collected, it is noticed that those habitats face severe threats due to extensive mining of lateritic rocks for brick production and other developmental activities. The species is provisionally assessed here as ‘Endangered’ [ EN B 1ab(ii,iii), B 2ab(ii,iii)].

AcknowledGementS

GG and AFJK thank the Science and Engineering Research Board, Govt. of India, for funds (Core Research Grant; file number CRG/2020/001605), and the Principal and Head, Department of Botany, Madras Christian College (Autonomous), Chennai for providing the necessary facilities. Authors are grateful to the Curators and Directors of ARI, B, BLAT, BM, BSI, BSID, C, CALI, E, G, K, L, MH, NY, P, RHT, S, SKU, SUK and US for granting permission to access the digital images or to consult the specimens personally; Mr. M. N. Pradeep and Mr. S. Siddharth, former Post Graduate students of Botany, Madras Christian College, Chennai, Mr. Veeresh H. Ari, Junior Research Fellow, Botanical Survey of India, Central National Herbarium, Howrah, and Mr. Abhishek Pujari, Mr. G. M. Krushnaji, Post Graduate students, Rani Channamma University, Belagavi, Karnataka for helping us during the field trips and Dr. M. Boobathiayyanar for scanning electron micrographs and Miss S. Madhura, for line drawings.