Raphiocarpus axillaris D.J.Middleton, 2021

Middleton, David, Nguy ễn, Q. B., Tr ần, H. Đ. & Leong-Škorničková, J., 2021, A NEW SPECIES OF RAPHIOCARPUS (GESNERIACEAE) FROM VIETNAM, Edinburgh Journal of Botany 78 (365), pp. 1-4 : 2-4

Raphiocarpus axillaris D.J.Middleton , sp. nov.

Affinities within the genus uncertain but differs from all other species by the combination of densely pubescent stems and leaves, symmetrical leaf bases, short axillary inflorescences, narrowly elliptic and densely pubescent calyx lobes free to the base, whitish to pale-pink corolla, and glabrous ovary. – Type: Vietnam, Vĩnh Phúc Province, Tam Đ ảo National Park, Tam Đ ảo 2, 21 ° 28′44.0′′N, 105 ° 37′39.6′′E, 1044 m, 22 ix 2011, Nguyễn Qu ốc Bình, Jana Leong-ŠKorniČKová, Tr ần H ữu Đăng VMN-B1494 (holotype SING; isotypes E, P, PR, VNMN). Figure 1 .

Perennial herb to c. 70 cm tall. Stems erect, semidecumbent at base, densely appressed hirsute throughout but slightly glabrescent with age. Leaves opposite, those of a pair more or less equal to rather unequal in size; petioles 1.5–4.5 cm long, densely appressed hirsute; blades symmetrical, elliptic, 6–16.5 × 3.2–7.8 cm, 1.9–2.6 times as long as wide, base cuneate, apex shortly acuminate, margin entire, appressed hirsute above and beneath,

more densely so on venation, 7–9 pairs of secondary veins, eucamptodromous, tertiary venation ramified. Inflorescences arising in the axils of lower leaves and below these in leaf scar axils, 1- or 2-flowered, up to 3 inflorescences arising from a single axil, 5–6 cm long (including flower); all axes with long gland-tipped hairs; peduncle 7–22 mm long; bracts narrowly elliptic, 3–4 mm long, with long gland-tipped hairs; flowers held almost horizontally to slightly pendent; pedicels 7–16 mm long. Calyx of 5 lobes free to base, lobes 6–7.5 × 1.5–1.9 mm, with long gland-tipped hairs outside, glabrous inside. Corolla whitish to pale pink, infundibuliform, 38–45 mm long, sparsely covered with long gland-tipped hairs outside, glabrous inside, with two prominent ridges ventrally from throat into upper tube, limb 2-lipped; tube 31–35 mm long, the lower 11–13 mm narrower but slightly wider at very base, the upper part widening towards throat; upper lip 2-lobed, 5.5–6.5 mm long, lobes 5.5–6.5 × 6.5–9.5 mm, sinus 4.5–6 mm deep; lower lip 3-lobed, 15–17.5 mm long, lateral lobes 7–9 × 8–10 mm, middle lobe 8–10.5 × 5.7–7.5 mm. Stamens 4, in 2 pairs, each pair adnate at their apices, divergent, glabrous, anther thecae confluent; posterior pair inserted at 17.5–19 mm from corolla base, filaments 10–11 mm long, glabrous, anthers 1–1.2 × 1.4–1.5 mm; anterior pair inserted at c. 17 mm from corolla base, filaments c. 15 mm long, glabrous, anthers 1.5–1.9 × 1.7 mm; staminode 1, slightly clavate, 3–4 mm long. Disc annular, weakly 5-lobed, 1.5–1.7 mm high. Pistil 22–25 mm long, glabrous throughout; ovary 16–17 mm long; style 5–7 mm long; stigma c. 1 mm, 2-lobed. Fruit green when young, mature fruit unknown.

Distribution. Currently known only from Tam Đảo National Park.

Etymology. The epithet axillaris refers to the short axillary inflorescences in this species.

Habitat and ecology. On rocks in montane evergreen broadleaved primary forest, from 1044 to 1101 m.

Conservation status. The species is currently known only from Tam Đảo National Park. As well as the collection from the type location, a second smaller population was seen and photographed along the Máy Giấy trail at 21 ° 26′59.2′′N, 105 ° 39′05.9′′E, which is about 4 km from the type population. Tam Đảo National Park is a legally protected area, but because each population is small enough to be affected by a stochastic event such as a tree fall,

we propose a provisional assessment of Vulnerable (VU D2) ( IUCN Standards and Petitions Subcommittee, 2019).

Figures

Figure 1. Raphiocarpus axillaris D.J.Middleton, sp. nov. A, Habit; B, flowers; C and D, inflorescences on bare stems; E and F, corolla from the front; G, very young fruit; H, undersurface of leaf. All photographs of the type collection, taken by J. Leong-Škorničková.