Coleus rafidahiae Kiew, 2021

Kiew, Ruth & Kamin, Imin, 2021, Coleus (Lamiaceae) in Peninsular Malaysia including two new species, PhytoKeys 186, pp. 93-110 : 93

4. Coleus rafidahiae Kiew sp. nov.

Diagnosis.

Unusual among Malaysian Coleus species in its branched inflorescence with yellowish white flowers (Figure 5 ). It resembles C. calcicola Murata from Thailand in its branched thyrsoid inflorescence with 1-flowered spaced cymes, in its calyx and yellowish white corolla but it is different in its larger laminas, 8.5-13.5 × 4-5.5 cm with longer petioles 2.5-8 cm long (vs. laminas 3-8 × 1.5-3 cm with petioles 0.5-1.5 cm long in C. calcicola ).

Type.

Peninsular Malaysia. Kelantan: Kuala Betis, Gunung Biol , 4°54.01'N, 101°45.33'E, 19 July 2017, Imin, Ong & Wan Shafiq FRI 87271 (holotype KEP!; isotype K!) .

Description.

Erect perennial, rather shrubby herb, to ca. 1 m tall. Stems brown and woody, branched, quadrangular, internodes 2-3 cm apart, ca. 4 mm thick, glabrous. Leaves: petiole slender, (2.5-)5.5-8 cm long, glabrous; lamina broadly elliptic to slightly ovate, 8.5-13.5 × 4-5.5 cm, base cuneate to truncate, margin crenate, apex acuminate, acumen 0.5-1.5 cm long, puberulous and densely dotted with minute glands on both sides; midrib white; veins inconspicuous beneath, 6-7 pairs on either side of midrib, midrib and veins slightly impressed above, slightly prominent beneath. Inflorescence terminal, branched lax thyrse, to 19 cm long, peduncle ca. 3.5 cm long, branches 5-6 cm long, 1.2-2.5 cm apart, glabrescent with a few minute hairs persisting near the apex, cymes 1-flowered, spaced on the branches. Bracts sessile, ovate, apex acute, 2-3 mm long, ciliate, pubescent, early caducous. Pedicels pubescent with gland-tipped hairs, ca. 2 mm long at anthesis, 3-4 mm in fruit. Flower with calyx campanulate, yellowish, pubescent with gland-tipped hairs, ca. 3.5 mm long at anthesis, in fruit 6-8 mm long, posterior lip erect, ovate, shortly acuminate at apex, constricted at base, 2-2.5 × 3-3.5 mm, margin entire; anterior lip 3.5-4 × 2-2.5 mm deeply divided into two teeth equal in length, ca. 2 mm long, slightly longer than posterior lip, lateral teeth obovate, 2-3 × 2-3 mm, spreading; tube 10-veined; corolla yellowish white, 7-12 mm long, minutely pubescent; posterior lobes minute rounded at apex; anterior lip ovate-oblong, 3-5 mm long, concave, shortly pubescent inside; tube ca. 7 mm long, not abruptly decurved above the calyx, dilated towards the throat; stamens included in anterior corolla lip; style bifid, subequal to anterior stamens; nectary exceeding ovary. Nutlets brown, ellipsoid, 1.75 mm long, 1.25 mm wide, smooth.

Distribution.

Endemic in Peninsular Malaysia, Kelantan: Kuala Betis, Gunung Biol. Known only from two specimens from the type locality (Map 1 ).

Provisional conservation status.

Critically Endangered B1ab(i,iii,iv). The species occurs on a single karst limestone hill that lies outside the network of Totally Protected Areas. It is known from a single small population. (Assessed by A.R. Rafidah).

Ecology.

Near the summit of a karst limestone hill at 325 m altitude.

Etymology.

Rafidah binte Abdul Rahman (b. 1981), KEP botanist, active contributor to revisions for the Flora of Peninsular Malaysia and the team leader of the project 'Towards a Conservation Strategy/Policy for Limestone Hills in Peninsular Malaysia: Understanding and Documenting Plant Biodiversity with Focus on Kelantan and Perlis Limestone Hills’ funded by the National Conservation Trust Fund (Figure 4 ).

Figures

Map 1. Distribution of Coleus hairulii (circle), C. kunstleri (triangle) and C. rafidahiae (star) in Peninsular Malaysia.

Figure 4. Coleus rafidahiae Kiew, sp. nov. A AR Rafidah on limestone hill with a Monophyllaea B inflorescence C flowering plant.

Figure 5. Coleus rafidahiae Kiew A flowering plant B portion of inflorescence C flower side view D flower from above E ovary F calyx in fruit G calyx opened H seeds side view. (All from FRI 87271. Drawn by N. Mohamad Aidil).