Zeuxine, Lindley, 1826

Li, Lin & Li, Shi-Jin, 2013, A new species of Zeuxine (Cranichidae; Orchidaceae) from Hainan, China, Phytotaxa 129 (1), pp. 65-68 : 67

Key to the species of Zeuxine from China

1. Leaves linear to linear-lanceolate, not stalked, base directly sheathing stem.............................................................. 2.

- Leaves ovate-lanceolate to elliptic, base contracted into a petiole-like stalk sheathing stem ..................................... 3.

2. Plants 4–24 cm tall; ovary and sepals glabrous .................................................................................... Z. strateumatica

- Plants 20–35 cm tall; ovary and sepals pubescent............................................................................... Z. membranacea

3. Midvein of leaves marked with silvery blotches or a white line (also on lateral veins in Z. gengmanensis ).............. 4.

- Leaves uniformly green or occasionally tinged with red............................................................................................. 8.

4. Lip entire, rhombic, not adnate to column, base contracted and lacking calli..................................... Z. integrilabella

- Lip bi-tripartite, base adnate to column, hypochile concave and containing 2 subulate, lamellate, or 2-3-digitate calli near base....................................................................................................................................................................... 5.

5. Epichile of lip transversely dilated but as broad as or narrower than hypochile, entire to shallowly bilobed ............ 6.

- Epichile of lip dilated, broader than hypochile, distinctly bilobed.............................................................................. 7.

6. Ovary sparsely hairy; sepals hairy abaxially ...................................................................................... Z. philippinensis

- Ovary glabrous; sepals glabrous ........................................................................................................... Z. goodyeroides

7. Stem stout, ca. 5 mm in diam.; lateral veins of leaves marked with white lines; flowers pink; hypochile containing 2 short, rounded calli............................................................................................................................... Z. gengmanensis

- Stem slender, 1–2 mm in diam.; lateral veins of leaves without white lines; flowers white or pale yellow; hypochile containing 2 2-3-digitate to narrowly lamellate calli ..................................................................................... Z. nervosa

8. Plants robust, 30–50 cm tall; leaves 5–12 × 3–7 cm .................................................................................... Z. odorata

- Plants slender to robust, to 30 cm tall; leaves 2–6 × 1–3 cm ....................................................................................... 9.

9. Leaves not usually withering at anthesis; epichile of lip as broad as or narrower than hypochile............................ 10.

- Leaves withering or pendulous at anthesis; epichile of lip dilated, broader than hypochile .................................... 11.

10. Leaves ovate-oblong, 3.0– 4.5 cm; bract entire, white hypochile containing 2 subulate, calli ................. Z. agyokuana

- Leaves ovate, 1.7–2.2 cm; bract ciliate, yellow hypochile containing 2 2-3-digitate calli......................... Z. ovalifolia

11. Lip T-shaped; epichile lobes diverging at right angles to axis of lip ......................................................................... 12.

- Lip Y-shaped; epichile lobes diverging at acute angles to axis of lip; epichile not mucronate at apex..................... 13.

12. Lip white ..................................................................................................................................................... Z. parvifolia

- Lip yellow ........................................................................................................................................................... Z. flava

13. Flower with lip 7–9 mm; hypochile containing 2 lamellate calli, each often with a linear extension; column wings lacking............................................................................................................................................................. Z. grandis

- Flower with lip to 6 mm; hypochile containing 2 subulate, hooked calli; column with triangular or transversely oblong wings .............................................................................................................................................................. 14.

14. Epichile rotated gently downward; epichile lobes obovate-flabellate, 2.0–2.5 × 2.0– 2.2 mm ........................ Z. affinis

- Epichile reflexed sharply downward from apex of mesochile; epichile lobes oblong to irregularly rhombic, 2.5–3.0 × 1.2–1.8 mm ...................................................................................................................................................... Z. reflexa