Billolivia

Trư ờng, Lưu H ồng, Đăng, Tr ần H ữu, Nhân, Ph ạm H ữu, Trung, Nguy ễn Tr ần Qu ốc, Đ ạt, Nguy ển Qu ốc & Long, Vũ Ng ọc, 2018, Two new species of Billolivia (Gesneriaceae) with yellow flowers from Vietnam, Phytotaxa 362 (2), pp. 227-232 : 231

Key to all known species of Billolivia

1. Calyx divided into 5 lobes almost to base..........................................................................................................................................2

- Calyx connate into a tube at base for at least 4 mm, margin 5-lobed.................................................................................................8

2. Calyx lobes> 3.5 mm wide................................................................................................................................................................3

- Calyx lobes ≤ 3 mm wide...................................................................................................................................................................5

3. Leaf margins minutely dentate or crenate, often appearing entire; calyx lobes 4.8–5.8 mm wide.................................... B. poilanei

- Leaf margins coarsely dentate; calyx lobes <4 mm wide...................................................................................................................4

4. Corolla lobes white, with purple lines in tube and onto lobes ................................................... B. cadamensis (syn. B. middletonii )

- Corolla lobes red, without purple lines in tube and onto lobes................................................................................................... B. kyi

5. Corolla lobes yellow...........................................................................................................................................................................6

- Corolla lobes white.............................................................................................................................................................................7

6. Leaf lamina ovate; peduncle to 8 mm long; corolla lobes citrus yellow; fruits translucent when ripe................................. B. citrina

- Leaf lamina obovate to oblanceolate; peduncle 10–52 cm long; corolla lobes bright yellow; fruits translucent violet when ripe ..... ............................................................................................................................................................................................ B. yenhoae

7. Leaf abaxially with hairs on venation and occasionally between veins; corolla 12–15 mm long; unfertilised ovary glabrous .......... ....................................................................................................................................................................................... B. minutiflora

- Leaf abaxially with pubescence throughout; corolla 18–25 mm long; unfertilised ovary pubescent at apex............. B. vietnamensis

8. Corolla throat with purple lines in tube and onto lobes.....................................................................................................................9

- Corolla throat without purple lines in tube and onto lobes..............................................................................................................10

9. Calyx lobes 3.5–4 mm wide; corolla tube about 15 mm long ........................................................................................... B. moelleri

- Calyx lobes 1.5–2 mm wide; corolla tube 20–22 mm long .................................................................................................... B. tichii

10. Calyx fused into a tube for 7–9 mm; corolla lobe tips pink or red; leaf margins coarsely dentate; petioles 9–18 cm long............ ................................................................................................................................................................................... B. longipetiolata

- Calyx fused into a tube for 4–6 mm; corolla lobe tips violet; leaf margins minutely dentate or appearing entire; petioles 6–12.5 cm long..................................................................................................................................................................................... B. violacea