Spelaeanthus vietnamensis D.J.Middleton, 2023

Middleton, David, 2023, A NEW SPECIES OF SPELAEANTHUS (GESNERIACEAE: DIDYMOCARPOIDEAE) FROM VIETNAM, Edinburgh Journal of Botany 80 (1993), pp. 1-5 : 2-4

Spelaeanthus vietnamensis D.J.Middleton , sp. nov.

Differs from Spelaeanthus chinii in the caulescent habit (vs acaulescent), the purple or blue corolla (vs white), and the larger flower (20–22 mm long vs c. 6 mm long). – Type: [ Vietnam], Tonkin, Massif du Tam Dao [Tam Đ ảo National Park ], 1200 m, v 1931, Pételot s.n. (holotype P [ P03934225 ]; isotypes B n.v., K, MO n.v., NSW n.v.). Figure .

Herb to 45 cm tall; stems densely glandular pubescent with hairs of greatly varying lengths. Leaves opposite; petioles 2.2–4.5 cm long, densely glandular pubescent with hairs of greatly varying lengths; lamina very thin, ovate, 2.5–11 × 1.3–6.2 cm, base cordate to obtuse, often asymmetrical, apex acuminate, margin coarsely serrate, 6–9 pairs of secondary veins, densely glandular pubescent above and beneath, the hairs on the venation generally longer. Inflorescences axillary, cymose, 3.6–8 cm long, 2- to 6-flowered, axes with pubescence as on petioles; peduncles 2–4.5 cm long; bracts small, caducous; pedicels 7–11 mm long. Calyx of 5 lobes free to base, the 2 lateral lobes of the dorsal 3 lobes slightly falcate, 4.4–5.5 × 1.2–1.7 mm, glandular pubescent. Corolla purple or blue, tube broad from base, somewhat dorsoventrally flattened, limb 2-lipped, lower lip straight, upper lip slightly reflexed, 20–22.5 mm long, outside sparsely short glandular pubescent, inside with short glandular hairs in upper part of tube dorsally; tube 11–13 mm long to sinus between upper and lower lips; upper lip 4.5–5.2 mm, lobes broadly orbicular, apices rounded, 3.2–3.5 × 6.7–7 mm; lower lip c. 11 mm long, lobes orbicular, apices rounded, lateral lobes 4.7–7 × 6.8–7.2 mm, central lobe 5–7 × 7–8 mm. Stamens inserted at

3–3.5 mm from corolla base; filaments narrow at base, curving and widening at c.1/3 length from base, 8–9 mm long, with short glandular hairs only in upper 1–1.5 mm; anthers 1.6–1.8 × 2.8–3.5 mm, thecae divergent, with occasional glandular hair, adnate face to face; staminodes near base of corolla, all of a similar size and c. 0.3 mm or lateral staminodes longer to 1 mm long. Nectary a thickened lobed ring, 0.6–0.8 mm long. Pistil c. 15 mm long; ovary 5–5.5 mm, densely pubescent with glandular hairs; style enantiostylous, 9.5–10 mm, densely pubescent with glandular hairs; stigma simple, not bifid. Fruit a capsule, almost straight to slightly twisted, 1.2–1.5 cm long. Seeds apiculate at each end, ovoid, c.0.5 ×

0.2 mm.

Distribution. Known only from Tam Đảo National Park, northern Vietnam.

Habitat and ecology. On rocks in primary forest, from 1064 to 1200 m.

Etymology. The epithet vietnamensis refers to the country where this species is endemic.

Proposed IUCN conservation category. Data Deficient (DD). Although the species is known from a few collections, only one of the collections is relatively recent. Tam Đảo National Park is a protected area; however, because the status of the populations and any possible threats are not known, an assessment should await a more detailed survey.

Additional specimens studied. VIETNAM: Vinh Phuc province: Tam Đảo National Park, Tam Đảo 2,

1064 m, 22 ix 2011, Nguyễn Qu ốc Bình , Jana Leong-ŠKorniČKová, Tr ần H ữu Đăng VMN-B1489 ( E, PR, SING, VNMN n.v.) ; Massif du Tam Dao, xi 1930, Pételot s.n. ( P [ P03511103 , P03934199 ]) .