Lepidagathis barberi Gamble (1923: 375)

Gnanasekaran, Gunadayalan, King, Anishkar Feroshwa Joy & Arisdason, Wilson, 2020, Taxonomy and lectotypification of Lepidagathis barberi (Acanthaceae), a steno-endemic species from Tamil Nadu, India, Phytotaxa 438 (2), pp. 151-155 : 151-154

Lepidagathis barberi Gamble (1923: 375) .

Type:— INDIA. Tamil Nadu: Madura distr. (plains), R. H. Beddome s.n. (lectotype designated here: K-000592220 [image!]). Fig. 1 .

Perennial subshrub, 40–70 cm high. Stems erect, well-branched, woody, angled, whitish, densely retrose-hairy when young; nodes slightly bulged; intermodal distance 0.5–1.5 cm long. Leaves sessile, opposite; lamina ovate-oblong, 1.7–2 × 0.5–1 cm, cuneate at base, 2 to 4 distinct spines intermixed with short-ciliolate hairs at margins, aristate at apex, glabrous, densely lineolate on both surfaces. Inflorescence a condensed spike, binate or ternate, capitately congested, axillary, subsessile, alternatively arranged, ovoid, 0.8–1 × 0.6–0.8 cm, villose; bracts 2, ovate, ca. 1 × 0.4 cm, aristate at apex; bracteoles oblong-lanceolate, ca. 0.6 × 0.2 cm, 3-veined. Calyx 5-partite; upper lip broadly elliptic, ca. 0.8 × 0.3 cm, 3-veined, hyaline, cartilaginous, long silky-hairy at margins, glabrous inside, silky-hairy outside; lower lip joined to about one half of the way up, ca. 0.6 × 0.2 cm. Corolla 2-lipped, whitish pink, upto 1.2 cm long, with short cylindric tube; tube ca. 0.4 × 0.5 mm; upper lip oblong, shallowly bifid; lower lip 3-lobed with brown spots at throat intermixed with hispid hairs, middle lobe larger than side lobes. Stamens 4, didynamous, 3–4 mm long, inserted; filaments slender, glabrous; anthers oblong. Ovary subovate, 1–1.5 mm across, 2-celled; style 6–7 mm long, slender; stigma minutely 2-lobed. Capsules oblong, ca. 5 mm long, compressed, 2-seeded; seeds ovoid, hairy ( Fig. 2 ).

Phenology: —Flowering and fruiting from July to October.

Distribution: — Lepidagathis barberi is endemic to India. It was recorded from Tamil Nadu (Erode, Madurai, Theni, Tirunelveli and Virudhunagar districts) and Karnataka (Mysore?). The consultation of representative specimens of this species from herbaria shows that other than G. Thomson s.n. (K-000592222), no specimen had been collected from the state of Karnataka. Thus the occurrence of the species in Karnataka is uncertain and needs further intensive field study to confirm.

Habitat: —Grows on dry sandy gravelly terrain of waste lands and scrub jungles.

Notes: —While describing this species, Gamble (1923) also cited Wight’s Icon. t. 456 along with other collections. Wight (1843) mistakenly identified the species as L. pungens Nees and provided description and illustration of flowering branch, corolla split-open showing the insertion of the stamens, abaxial and adaxial views of anthers, bracteoles and an immature capsule opened. Since, the well-preserved original specimens are available, the Wight’s icon has not been considered for the lectotype.

Vajravelu (1990) assessed the threat status of this species as ‘Rare’ as it was poorly represented in Indian herbaria. Furthermore, he stated that this species could not be recollected after an intensive field visits from the districts where it had been recorded earlier and this might be because of the habitat loss. However, during the present field visit to Virudhunagar district it was noted that the occurrence of this species is very common but the habitat is severely altered due to urbanisation.

A key to differentiate this species from its allied, L. pungens is given below as it has been often confused and mistakenly identified as the latter.

1a. Leaves ovate; inflorescence compactly ovoid with adpressed bracts, lower calyx lobes joined to about one half of the way up ...... ............................................................................................................................................................................................. L. barberi

1b. Leave ovate-oblong; inflorescence broadly ovoid with spreading bracts; lower calyx lobes joined to about one third of the way up ....................................................................................................................................................................................... L. pungens

Specimens examined: — INDIA, Karnataka, Maisor (Mysore) & Carnatic , s.die, G. Thomson s.n. (K-000592222) . Tamil Nadu, Erode district, Arachalur , 600’, 17 October 1905, C. E. C. Fischer 466 ( CAL) ; Madurai district, Madura , without specific locality, January 1911, A. Meebold 13815 ( CAL) ; Tirunelveli district, Koilpatti , 18 July 1901, C. A. Barber 3427 (K-000592221 & MH) ; Theni district, Old Butlagundu , 400 m, 02 October 1977, M. Chandrabose 51640 ( MH) ; Virudhunagar district, Sattur , 21 July 1945, D. Daniel Sundarraj 14751 ( MH) ; Sattur , 21 July 1954, D. Meenakshi Sundaram 22233 ( MH) ; Sattur , 300 m, 10 October 2019, G. Gnanasekaran 12734 (Madras Christian College Herbarium) .

Figures

FIGURE 1. Lectotype of Lepidagathis barberi Gamble (R.H. Beddome s.n., K-000592220).

FIGURE 2. Lepidagathis barberi Gamble:A. Habit; B. Flowering-twig.