Anisomeles tamilnadense Ramasubbu & Bechu, 2025

Bechu, Punnen Abraham, Ramasubbu, Raju, Spurgeon, Edwin Kirubai Dass, Venkatesh, Palanivel & Kalaiselvan, Karuppasamy, 2025, Anisomeles tamilnadense (Lamiaceae), a new species from Tamil Nadu, India, Phytotaxa 711 (2), pp. 202-208 : 204-207

Anisomeles tamilnadense Ramasubbu & Bechu sp. nov. ( Figures 1–3 ).

TYPE:— INDIA, Tamil Nadu, Dindigul District, near Gullalagundu, Sirumalai Hills , 10°09’46”N, 77°55’12”E ; 245 m elev., 24 March 2023, R. Ramasubbu & P. A. Bechu, GUD 384 (holotype MH!, isotype GUD!) .

Erect, or sometimes straggler shrub, ca. 1.2–1.7 m high. Stem above and rachises erect, 4-angled without patent hairs hispid, retrorse, shortly curved, scattered to crowded, no glandular hairs stalked. Leaves cauline, ovate-lanceolate, 45–105 × 22.5–47.3 mm, 2.0–2.2 times longer than breadth of leaf, base narrow-cuneate rarely attenuate, dark green abaxially, pale green adaxially, marginal lobes serrate, regular, 19 to 26 on both sides, obtuse or acute, 0.2–0.9 mm depth; petioles longer, 11–16 mm, 18–24% of leaf length, indumentum erect on upper surface of lamina, curved, non-glandular, 0.5–1.3 mm; dense (<0.20 mm) or moderately dense (0.20–0.40 mm) hairs, glands sessile, 8–36 mm ²; indumentum lanate at adaxial, tangled or erect or curved, non-glandular, 0.6–1.2 mm, very dense on veins viewing at 40x, changing abruptly from leaves to flower bracts. Bracts spathulate, 2.3–8.1 × 1.0– 3.2 mm, purplish tinge on margin, bracteoles linear or narrowly spathulate, purplish tinge or line along apex to middle, 3.3–6.1 × 1.5–3.1 mm, bracteoles not constantly surpassing verticils. Verticils developed as uninterrupted terminal inflorescence, sometimes overlapped at apex; cymes dichasial at base, either twice or monochasial (more or less globose), ca. 3–6 floral buds/ monochasium, peduncle 0.3–1.0 mm long, at lowermost clusters. Corolla tube longer (20 %) than calyx, 122–146 mm, annulus 3.2–4.1 mm from corolla base, annulus hairs 4.6–6.6 mm longer. Corolla upper lip broadly elliptical, 4.1–6.9 mm, without glandular hairs upon outer side; floral lower lip 4–6.9 mm, to the end of lateral lobes, entire 8.5–10.7 mm, with ≤ 100 non-glandular hairs at platform. Stamens 4; the longest, 11.9–14.9 mm long from base of corolla tube, hairs around middle of the filaments 0.8–1.3 mm long, mainly along middle part, purplish. Style longer than stamen, projected exterior to corolla tube, deep purplish, 16.1–17.2 mm long; stigma bilobed, longer lobe 1.1–1.5 mm, shorter lobe 0.7–0.9 mm. Fruiting calyces cylindrical or obconical, 1.0– 1.5 mm apart on rachilla, 9.6–12.0 × 2.8–3.7 mm, external surface covered with hairs of various sizes, hairs glandular, 0.4–1.2 mm long, rarely eglandular; attenuated lobes, 3.0– 5.1 mm long. Fringe hairs in calyx equal length all around or slightly extended at sinus, 0.2–0.6 mm at apex, 0.6–0.9 mm long the sinus tip, thick ring of long hairs on the inner tube at medial. Nutlets 2, 2.7–2.9 × 1.8–2.0, blackish.

Phenology: The flowering period was observed in September, with a peak (individuals with more flowers) in

November, whereas the fruiting period was observed at the end of October with peak fruiting in December. Etymology: The species is named after Tamil Nadu, where the type locality is located. Distribution: Distributed in scrub jungles from 245 to 260 m a.s.l., Sirumalai Reserve Forest, Dindigul District,

Tamil Nadu, India.

Conservation status:— Anisomeles tamilnadense is preliminarily assessed as Critically Endangered ( CR) under criteria B and D of the IUCN guidelines ( IUCN 2024). The extent of occurrence ( EOO) of this species has been assessed as about 15.732 km 2, and the area of occupancy ( AOO) has been recorded as about 20.0 km 2, with about 45 mature individuals (Figure 4).

F FIGURE 4. a) Distribution map of Anisomeles tamilnadense .

Paratypes: TYPE:— INDIA, Tamil Nadu, Dindigul District, near Gullalagundu, Sirumalai Hills, 10°09’46”N,

77°55’12”E; 245 m elev., 12 December 2024, R. Ramasubbu & P. A. Bechu 392 ( GUD) .

Figures

FIGURE 1. Anisomeles tamilnadense: a) adult shrub at flowering; b) inflorescence twig; c) indumentum in stem; f) leaf morphology; g) leaf apex; h) leaf margin; A. malabarica: d) leaf morphology; i) leaf margin; A. indica: e) leaf morphology; j) leaf margin

FIGURE 2. Mature flower of Anisomeles indica (a), A. tamilnadense (b) and A. malabarica (c).

FIGURE 3. Floral parts of Anisomeles tamilnadense. a) bract; b) bracteole; c) calyx; d) calyx with bracteole; e) stamen; f) closer view of bilabiate corolla; g) androecium; h) stigma; i) ovary; j) seeds.