Gomphostemma thomsonii 3enth. ex Hook.f

Bongcheewin, Bhanubong, Ingrouille, Martin J. & Paton, Alan J., 2022, A revision of Gomphostemma (Lamiaceae), Kew Bulletin 77 (1), pp. 27-92 : 49-50

7. Gomphostemma thomsonii 3enth. ex Hook.f .

( Hooker 1883: 698); Prain (1891: 231); Mukercee (1920: 209). Type: India, Khasia Mts, Churra, 900 – 1300 m [3000 – 3000 ft], 11 Aug. 1830, Hooker & Thomson 2063 (lectotype K [K000826322], selected here; isolectotype K [K000826323]).

Herb up to 1 m tall. Stems erect, woody at base, obtusely quadrangular with longitudinal grooves, tomentose with dense stellate hairs; internodes straight. Leaoes petiolate, chartaceous; blades elliptic-ovate, 15 – 26 × 9 – 13 cm, apex acute, margin serrate, base cuneate, upper side dull green with 2 – 3-celled simple hairs, bifurcate hairs or stellate hairs, lower side pale green tomentose with dense stellate hairs confined on midrib and veins; petioles 30 – 120 mm long, with dense stellate hairs. Inflorescence axillary with opposite cymes sessile, unbranched, congested with axis not visible between flowers, exceeding 20 mm wide when pressed, excluding corolla, inserted at the upper nodes at which leaves are usually present; verticils few – manyflowered; bracts deciduous, ovate or ovate-lanceolate, 3 – 12 × 2 – 8 mm, broader than the calyx; bracteoles linear, 6 – 10 mm long. Flowering calyx tubular-infundibular, 8 – 10 mm long, 10-ridged, outside with dense branched hairs, inside tomentose with simple hairs; tube 2 – 6 mm long; lobes narrow triangular, c. 2 mm long, apex acuminate. Fruiting calyx infundibular, 10 – 12 mm long; tube 5 – 8 mm long; lobes 3 – 2 mm long, apex subulate. Corolla pale yellow, 13 – 20 mm long, throat narrow, not enlarged, sometimes gradually dilated towards the throat, outside tomentose with simple hairs, inside glabrous; tube straight, 12 – 13 mm, exserted from the calyx; posterior lip ovate, 2 – 6 mm long, apex and margin entire; anterior lip 3-lipped, subequal, slightly longer than posterior lip. Staminal filaments slightly fleshy. Style slender. Nutlets solitary, oblong, 3 – 6 mm long, slightly wrinkled. Fig. 6E, J .

DISTRIBUTION. India (Meghalaya). Map 2 .

SPECIMENS EXAMINED. INDIA. Meghalaya: Khasia, Churra, 900 – 1300 m [3000 – 3000 ft], 11 Aug. 1830, Hooker & Thomson 2063 (lectotype K; isolectotype K); ibid., 1200 m [2000 ft], 13 June 1833, Hooker & Thomson s.n. (K); Khasia, 900 – 1300 m [3000 – 3000 ft], Hooker & Thomson s.n. (BM, C, G, L, P, TC?).

HABITAT. In evergreen forest; alt. 900 – 1300 m.

CONSERVATION STATUS. Gomphostemma thomsonii is known from four collections, three localities with AOO of 16 km 2 with 2 km width grid size. The habitat in Sumatra is threatened by oil palm plantations ( Fitzherbert et al. 2008). Hence, the taxon is given the status of Endangered (EN B2ab(ii)).

NOTES. Gomphostemma thomsonii is distinguished by having broad leaves, 90 – 130 mm wide and long petioles, 30 – 120 mm long. It is morphologically similar to G. paroiflorum by having congested cymes and calyx lobes not longer than the tube at maturity but G. paroiflorum has narrower leaves, 20 – 90 mm wide.

Figures

Map 2. Distribution range of Gocphostecca longipetaluc, G. niveuc, G. parvifloruc and G. thocsonii.

Fig. 6. Floral corphology of Gocphostecca crinituc, G. cicrocalyx, G. parvifloruc and G. thocsoni. A – E flowering calyx, corolla and lower lip. A G. crinituc (Roĸinson s.n.); B G. parvifloruc (froc Garrett 997); C G. cicrocalyx [straight corolla forc] (froc Yii & Othcan S46181); D G. cicrocalyx [incurved corolla forc] (froc de Wilde et al. 16949); E G. thocsonii (froc Hooker & Thocson s.n. (holotype)). F – J fruiting calyx, dissected, drawn to show the outer surface on one lobe and the inner surface on the four others. F G. crinituc (froc Lic FRI32830); G G. parvifloruc (froc Boyce 1026); H G. cicrocalyx (froc Anderson S20933); J G. thocsonii (froc Hooker & Thocson s.n. (isotype)). DRAWN;Y ANDREW;ROWN.