Ixora gadgiliana Balan & Robi, 2025

Balan, Anoop Puthuparambil & Jose, Robi Aloor, 2025, Ixora gadgiliana sp. nov. (Rubiaceae: Ixorideae), a new species from Southern Western Ghats, India, Adansonia (3) 47 (4), pp. 27-30 : 28

Ixora gadgiliana Balan & Robi , sp. nov.

( Fig. 1 ; Table 1 )

Ixora gadgiliana Balan & Robi , sp. nov. is allied to Ixora lawsonii Gamble in its general appearance, especially terminal, dense, short-peduncled corymbose inflorescence, but clearly distinct from the latter by the arborescent (vs shrubby) habit, obovate-oblanceolate (vs ovate or elliptic-oblong) leaves, up to 9 cm long (vs 10-16 cm long) lamina, and 7-9 (vs 10-16) pairs of secondary veins, up to 1 cm long, white (vs 1.5 cm long, pinkish white) flowers, 0.5 mm long, deltoid (vs 4 mm long, linear) calyx lobes and beaked (vs not beaked) anthers.

TYPE MATERIAL. — India • Kerala, Idukki, Urumbikara ; ± 1200 m a.s.l.; 14.I.2022; Balan Anoop P. & Robi A.J. 327; holo-, KFRI!; iso-, BAM!, MH!

DISTRIBUTION, HABITAT AND ECOLOGY. — Ixora gadgiliana sp. nov. is so far known only from few populations in the Urumbikara Hills of Idukki district, Kerala, India. It is often found in isolated evergreen forest patches in between grasslands at an altitude of ± 1200 m. Ligustrum robustum (Roxb.) Blume subsp. walkeri (Decne.) P.S. Green , Litsea vagamonia Robi & Vajayash. , Mussaenda hirsutissima (Hook. f.) Hutch. ex Gamble , Neolitsea foliosa var. scrobiculata (Meisn.) Chakrab. , Eurya japonica Thunb. , Strobilanthes pulneyensis C.B. Clarke , Ternstroemia gymnanthera (Wight & Arn.) Bedd. , Zanthoxylum ovalifolium Wight , etc. are the common associates of I. gadgiliana sp. nov.

PHENOLOGY. — Flowering observed from December to January; Fruiting not seen even after observing for three consecutive seasons.

ETYMOLOGY. — The epithet is named in honour of Prof. Madhav Dhananjaya Gadgil, a renowned Indian ecologist, in recognition of his contributions towards the conservation of Western Ghats, one of the biodiversity hotspots in India.

CONSERVATION STATUS. — Very rare in its known distribution range and the population is restricted to two isolated locations. The type locality of the new species is located in a landslide-prone area identified by the Kerala State Disaster Management Authority (KSDMA). Hence, the new species is under threat due to natural calamities like landslides and soil erosion. It is located far away from the surveillance of forest department and therefore facing serious threat due to human encroachments. The conservation status of this species is proposed as Data Deficient. Further survey for this taxon is suggested.

ADDITIONAL SPECIMENS EXAMINED. — India • Kerala, Urumbikara Hills ; ± 1200 m a.s.l.; 07.I. 2023; Balan Anoop P. & Robi A.J. 511; BAM !

DESCRIPTION

Much branched, evergreen trees, up to 5 m tall; stem often covered with mosses and ferns; branchlets slender, glabrous; internodes short (0.8-1.5 cm). Stipules interpetiolar, ovate-truncate, 2-3 × 2-2.5 mm, glabrous, awn 2–3 mm long. Leaves opposite; petioles 4-6 mm long, thick, glabrous; lamina obovate-oblanceolate, 6-9 × 1.5-2.5 cm, acute-shortly acuminate at apex, cuneate at base, subcoriaceous, margins flat, glabrous on both sides; secondary veins 7-9 pairs, prominent beneath. Bracts supporting inflorescence foliaceous, 1.5-2.5 × 0.8-1.0 cm, ovate, shortly-acuminate at apex, obtuse at base, persistent. Inflorescence terminal, 4-5 cm long, 4 cm across, trichotomously branched corymbose cymes; peduncle branched at 1.5-2 cm from the base; branches 1.5-2 cm long, glabrous; bracts supporting flowers linearlanceolate, 1-1.2 mm long, puberulous. Flowers subsessile, bracteolate; bracteoles 0.6-0.7 mm long, lanceolate, puberulous. Calyx tube 0.8-1 mm long, glabrous; lobes 4, 0.5 mm long, deltoid. Corolla white, glabrous; tube 8 mm long, slightly broadened towards apex; lobes 4, 2.2 × 2 mm, ovate-oblong, obtuse at apex, reflexed. Stamens 4, attached at mouth, alternating with corolla lobes; filaments 0.5 mm long; anthers sub-basifixed, beaked, 2 mm long, tip pointed, sagittate at base. Ovary 2-celled, ovule 1 in each cell; style slender, 1 cm long, tip fusiform, longitudinally cleft forming two stigmatic lobes of c. 1 mm long. Fruits unknown.

Figures

FIG. 1. — Ixora gadgiliana Balan & Robi,sp. nov.:A, habitat;B, stem;C, flowering twig;D, stipule;E, inflorescence;F, single flower;G, bract;H, bracteole;I, calyx; J, corolla lobe; K, Flowering twig of I. lawsonii. Scale bars: C, D, E, K, 1 cm; F, 5 mm; G, H, I, 1 mm; J, 2 mm.