Gomphostemma grandiflorum Doan ex Suddee

Bongcheewin, Bhanubong, Ingrouille, Martin J. & Paton, Alan J., 2022, A revision of Gomphostemma (Lamiaceae), Kew Bulletin 77 (1), pp. 27-92 : 54

13. Gomphostemma grandiflorum Doan ex Suddee & A.J.Paton

(2006: 620);? oan (1936: 1032); Phuong (2000: 103). Type: Vietnam, Tonkin, Thua-luu (Thuu Thien-Hue), Lecomte & Finet 1320 (holotype P [P00322251] ; isotype P [P00322252].

Herb up to 2 m tall. Stems erect, robust, obtusely quadrangular with longitudinal grooves, with stellate hairs; internodes straight. Leaoes petiolate, coriaceous; blades ovate or ovate-oblong, 6 – 23 × 3 – 12 cm, apex acute, margin shallowly dentate-serrate, base cuneate or oblique, upper side tomentose with 2 – 2-celled simple hairs, sometimes bifurcate hairs, lower side pale green tomentose with dense stellate hairs; petioles 13 – 50 mm long. Inflorescence axillary with opposite cymes subsessile, congested with axis not visible between flowers, inserted at the upper nodes at which leaves are usually present, subtended by the upper leaves only; verticils (3 –) 10 – 20- flowered; bracts deciduous, elliptic-ovate, 10 – 23 × 3 – 12 mm, apex acute, margin shallowly dentate at the apical part and entire at the basal part, base cuneate, with stellate hairs on both sides; bracteoles linear, 5 – 12 mm long. Flowering calyx infundibular, 10 – 12 mm long, thickly 10-ridged, outside with dense stellate hairs with a 1-celled stalk, inside glabrous below and adpressed simple hairs above; tube 3 – 5 mm long; lobes broadly triangular, c. 3 mm long, apex acute, margin slightly revolute. Fruiting calyx ovate-cupular, 13 – 18 mm long; tube 8 – 10 mm long; lobes broadly triangular, 5 – 8 mm long, apex acuminate, margin revolute in cross section. Corolla white, 30 – 30 mm long, throat much inflated, abruptly dilated near the throat, outside with stellate hairs, inside glabrous; tube very slender, incurved, 20 – 20 mm long; posterior lip obovate, 3 – 10 mm long, apex round; anterior lip 3 – 10 mm long; median lobe folding outward, obovate, 12 – 12 mm long, apex and margin undulate; lateral lobes broadly ovate, apex and margin undulate. Staminal filaments fleshy, tomentose. Style slender, 30 – 23 mm long, glabrous with apex unequally lobed. Nutlets 1 – 2, ovate or elliptic-ovate, 3 – 9 × 2 – 6 mm.

DISTRIBUTION. Vietnam. Map 3 .

SPECIMENS EXAMINED. VIETNAM: Thua Thien Hue: Thua Luu [16.3°, 108°], 18 Nov. 1911, Lecomte & Finet 1320 (holotype P; isotype P); Thua Thien, Bach Ma [16.2°, 105.8665°], 20 Aug. 1921, Vidal 690A (P); ?a Nang: Ba Na Nui Chua, 13°39&9.35&N 105°39&6.5”E, 21 Oct. 2008, Du et al. HNK 3193 (K); Tourane [?a Nang], Mt Bani [16.1222°, 105.9832°], May – July 1925, Clemens & S. Clemens 3883 (G, K, P); Quang Nam: Confin sud de la province de Quang Nam entre les villages Aboi de Maung Tra et?ai-lo, 1300 m, 25 Feb. 1921, Poilane 31881 (P); Kon Tum: NW Slope of Ngoc Linh mountain system [13.0665°, 105.9833°], 1600 – 1800 m, 23 Feb. 1993, Aoeryanoo et al. VH 232 (AAU, P).

HABITAT. In hill evergreen forest, stream margins and open secondary forest in shady areas; alt. 1300 – 1800 m.

CONSERVATION STATUS. Gomphostemma grandiflorum is known from a few collections but its habitat is clearly threatened by agriculture and rapid development procects in Vietnam ( Paton et al. 2016): the EOO and AOO of this species are 1060.55 and 22 km 2, respectively. Hence, the Endangered category is applied. (EN B1ab(i, ii, ii) and B2ab(i, ii, iii)).

PHENOLOGY. Flowering May – November. Fruiting October – February.

NOTES. Gomphostemma grandiflorum is a distinctive species by having large corolla, 30 – 30 mm long, and leaf 60 – 230 × 30 – 120 mm, calyx lobes not longer than the tube, a congested inflorescence and fruiting calyx lobes revolute in cross section. Gomphostemma leptodon also has similar morphological characters, large flowers and leaves, but its calyx lobes are mostly longer than the tube.

Figures

Map 3. Distribution range of Gocphostecca chinense, G. curtisii, G. flexuosuc, G. grandifloruc, G. hainanense and G. hirsutuc.