Billolivia longipetiolata D.J.Middleton & Luu, 2014

Billolivia longipetiolata D.J.Middleton & Luu View in CoL , sp. nov. ( Fig. 3 View FIGURE 3 , 4 View FIGURE 4 )

Distinguished from all other species of Billolivia by the generally longer petioles. It is most similar to Billolivia violacea from which it can be distinguished by the long petioles, the coarsely dentate lamina margin (minutely dentate in B. violacea ), the calyx fused into a tube for 7–9 mm and the lobes somewhat bilabiate (4−6 mm and not noticeably bilabiate in B. violacea ), and the pink or red tips to the corolla lobes (violet in B. violacea ).

Type:— VIETNAM. Lam Dong Province, Bidoup – Nui Ba National Park , 1400 m alt., 22 February 2012, Luu Hong Truong & Pham Huu Nhan BD624–BD629 [a single gathering in sequential number series] (holotype SGN [BD628] , isotypes SGN [BD625, BD626] , E [BD624, BD627, BD629 ]).

Terrestrial herb; stems densely pubescent with brown multicellular uniseriate hairs to 5 mm long. Leaves alternate; petioles 9−18 cm long, densely pubescent with hairs to 3.5 mm long; lamina ovate to elliptic, 7.7−17 × 4.8−7.4 cm, 1.6−2.6 times as long as wide, base rounded to cuneate, apex short acuminate to obtuse and apiculate, margin coarsely dentate, secondary venation 6–12 pairs of veins on each side of midrib, tertiary venation only weakly visible, adaxial lamina glabrous or with only the very occasional short hair, margin densely ciliate, abaxial lamina with appressed brown hairs to 4 mm long, mostly much shorter, on midrib and venation, sometimes also on lamina between veins. Inflorescences axillary, 4–12-flowered; peduncle 1–3 cm long, sparsely pubescent; bracts ovate, to 11 × 5 mm, apex acute, pubescent; pedicels 13–25 mm long, densely pubescent. Calyx 9–16.5 mm long, composed of a tube and a weakly bilabiate apex, the lower lip with 2 lobes and the upper with 3 lobes, sparsely to densely brown pubescent outside, glabrous inside, all lobes deltoid, apices acute, relative sizes of calyx parts very variable even within an individual; tube 7–9 mm long; upper lip 3.5–8.5 mm long with lobes 2.3–6.4 × 1.2–3 mm; lower lip 4.2–7.2 mm long with lobes 2.2–6 × 1.8–2.5 mm. Corolla 24–34 mm long, composed of a narrow tube which slightly flares towards oblique mouth and a 2-lipped limb with lobes recurved, tube and base of lobes white outside and inside, tips of lobes pink or red outside and inside; tube 20–28 mm long; upper lip 2-lobed, 9.5–10.5 mm long, sinus between lobes 8.5–9 mm, lobes squarish or oblong, 8.5–9 × 5.5–8.5 mm, apices truncate to rounded; lower lip 3-lobed, c. 11 mm long, lobes squarish to slightly obovate, apices truncate to rounded, lateral lobes 8–12 × 7.5– 8 mm, medial lobe c. 10 × 7 mm; outside glabrous at base, densely pubescent with multicellular uniseriate hairs distally, sparser on outside of lobes but glabrous on edges covered in bud, inside mostly glabrous but with shortly stalked to subsessile glands at top of tube and bases of upper and lateral lobes, sparse over inside of lower lobe. Stamens inserted at 14–21 mm from corolla base; filaments curved to S-shaped, 4.5–6 mm long; anthers 2.1 × 1.5 mm; lateral staminodes 1.5–2.5 mm long, medial staminode 1–1.2 mm long. Disc a complete or almost complete annular and crenate ring but either missing a section dorsally or the disc much lower dorsally, 0.7–1.4 mm long. Ovary 4–6 mm long, glabrous; style 7–22 mm long, sparsely glandular puberulent; stigma lobes 1.2–1.8 mm long. Fruit completely enclosed in persistent calyx, fusiform, c. 9 mm long, 3.5 mm wide, glabrous except for few hairs at extreme apex. Seeds ellipsoid, 0.5 × 0.3 mm.

Etymology: — In reference to the long petioles.

Distribution: — Vietnam, Lam Dong Province.

Ecology: — Along streams in submontane tropical evergreen closed forest at 1400–1950 m altitude.

Proposed IUCN conservation status: — Data Deficient (DD) ( IUCN 2001, 2012). The known localities of this species cover an area of far less than 100 km 2 which would qualify it for Critically Endangered if there were also associated threats. Within the National Park there are no known threats but what is not yet known is whether this species may also be found in other nearby forests such as Phuoc Binh and Chu Yang Sin and if there are threats associated with those possible populations. Further survey work in the region is necessary before a definitive conservation assessment can be made.

Additional specimens studied: — VIETNAM. Lam Dong: Bidoup – Nui Ba National Park , 1400 m alt., 21 February 2012, Luu Hong Truong & Pham Huu Nhan BD612-BD613 ( SGN) ; Lac Duong District, Da Chay Municipality, 35 km NE of Dalat City, W slope of Gia Rich mountain ridge , 1800–1900 m, 18 March 1997, L.V. Averyanov VH2857 ( E, P) ; Lac Duong District, Da Chay Municipality, 31 km NE of Dalat City, W slope of Bi Dup [Bidoup] mountain, vicinity of Klong Lanh Village , 1850–1950 m, 20 March 1997, L.V. Averyanov VH2951 ( MO, P) .

Of the new species described here this is the one that has been collected most often. It is most easily recognised by the long petioles. There is an overlap in the range of petiole lengths known in this species and Billolivia violacea but in B. longipetiolata there is always at least one petiole on a plant that is longer than any found in B. violacea .