Chroesthes lanceolata (T. Anderson) B. Hansen, 1983

Yunoh, Siti-Munirah Mat, 2021, Chroesthes (Acanthaceae) in Peninsular Malaysia, including a new species from Kelantan and a new record from Terengganu, PhytoKeys 174, pp. 127-146 : 127

Chroesthes lanceolata (T. Anderson) B. Hansen Fig. 6

Chroesthes lanceolata ( T. Anderson ) B . Hansen, Nordic J . Bot. 3: 209. 1983; Hu , J. C ., Deng, Y. F ., Daniel, T . & Wood, J. R. I . Acanthaceae . In: Wu , Z. Y ., Revan, P . & Hong, D. Y. ( Eds. ) Flora of China 19: 472. 2011. Basionym : Asystasia lanceolata T . And., J . Linn. Soc., Bot. 9: 524. 1867. Type: Myanmar, Pegu, Thaungyin, Brandis s.n. (holotype CAL) .

Description.

Shrubs 0.5-3 m tall, anisophyllous. Stems terete, slender, rarely branched, glabrous. Leaves petiole 1-2.5 cm; leaf blade elliptic to oblanceolate to lanceolate, 10-16 × 3-7 cm, both surfaces glabrous, secondary veins 6-9 on each side of mid-vein, base cuneate, margin entire or sub-sinuate, apex acuminate. Inflorescence thyrses 3-7 cm; cymes sessile, 1-3-flowered; peduncles ca. 2 cm; bracts elliptic to broadly lanceolate, 3-9 × 1-3 mm, apex acute, glandular-pubescent; bracteoles narrowly elliptic to broadly lanceolate, 4-9 × 0.7-1.2 mm; pedicel 1-5 mm long. Calyx 1-1.6 cm, outside glandular-pubescent; posterior lobe lanceolate, ovate or subelliptic; anterior lobes connate to two-thirds of their length. lateral lobes linear-lanceolate. Corolla white with pink or purple spots, ca. 2.5 cm, outside pubescent; tube basal portion ca. 9 mm, throat ca. 1.5 cm; upper lip two-lobed; lower lip three-lobed. Stamens 4, included in throat; filaments 1-1.2 cm, glabrous; anther thecae 2.1-2.3 mm, pubescent at the apex and along sides, basal spur pointed; ovary apex pubescent; style ca. 2.5 cm. Capsule subellipsoid to obovoid, 1.2-1.6 cm, glabrous or only at apex pubescent, four-seeded. Seeds subcircular in outline.

Distribution.

Myanmar, N Thailand, N Laos, N Vietnam, SW China (Yunnan), Malaysia. In Peninsular Malaysia, recorded from one specimen collected from the trail to Gunung Padang, Ulu Brang, Terengganu in 2010 ( FRI 66129 ) (Map 1 ).

Ecology.

In Peninsular Malaysia, found in a lowland dipterocarp forest at 473 m a.s.l., under a canopy near a small river. (Trail to Gunung Padang).

Conservation status.

Critically Endangered B 2 ab(ii). Following the IUCN Red List Categories and Criteria ( IUCN 2019), this species is assessed as critically endangered at a national level in Peninsular Malaysia because it is currently known from only one specimen in one locality. It is certainly a very rare species. The forest area is lowland dipterocarp forest which was previously logged in the past and it is not a Totally Protected Area. Globally, its conservation status possibly lists it as least concern ( LC), by its wide range distribution.

Specimen examined.

Terengganu: Hulu Terengganu, Ulu Brang, Ummul-Nazrah et al. FRI 66129 ( KEP) .

Figures

Map 1. Distribution of Chroesthes faizaltahiriana (▲) and C. lanceolata (■) in Peninsular Malaysia.

Figure 6. Chroesthes lanceolata (T. Anderson) B. Hansen collected from Gunung Padang, Terengganu. (FRI 66129).