Key to species of Mitreola in China

1. Perennials ...........................................................................................................................................................................................3

- Annuals...............................................................................................................................................................................................2

2. Plants 5–10 cm tall; leaf blade 0.5–2 cm long; stems terete ...................................................................................... M. petiolatoides

- Plants 10–50 cm tall; leaf blade 4–7 cm long; stems 4-angled ........................................................................................ M. petiolata

3. Stem 4-angled or acaulescent; leaf petiolate or sessile; inflorescences terminal ...............................................................................8

- Stem terete; leaf petiolate; inflorescences terminal or axillary ..........................................................................................................4

4. Stems erect; stamens inserted at corolla tube base.................................................................................................................... M. liui

- Stems erect or creeping; stamens inserted at or near corolla tube middle..........................................................................................5

5. Lateral vein 4–6 pairs; bracts linear .................................................................................................................................. M. pingtaoi

- Lateral veins 7–10 pairs; bracts narrowly elliptic or lanceolate.........................................................................................................6

6. Plants 3.0– 8.5 cm tall, leaf blade bullate, veins in abaxial surface purplish red, corolla light purple .................. M. bullata sp. nov.

- Plants up to 60 cm tall, leaf blade smooth, veins in abaxial surface green, corolla white .................................................................7

7. Leaf apex acute; stipules triangular; stems erect, nearly terete ............................................................................... M. yangchunensis

- Leaf apex acuminate to obtuse; stipules degeneration or reduce to a narrow leaf sheath between petioles; stems creeping branchlets 4-angled when young, becoming terete......................................................................................................................... M. pedicellata

8. Stems conspicuous, creeping; leaves occurring along length of stem or clustered at stem apex, petiole 0.3–1.2 cm long................. ......................................................................................................................................................................................... M. reticulata

- Stems inconspicuous; leaves in a basal rosette, sessile ......................................................................................................................9

9. Leaf blade 3.5–7 cm long, apex acute, nerves purple abaxially; capsule horns incurved..................................... M. purpureonervia

- Leaf blade 7–30 cm long, apex obtuse to rounded, nerves light green; capsule horns erect ...........................................................10

10. Leaf blade spathulate to oblanceolate; 5–7 veins on each side; stamens inserted at the middle of corolla tube ....... M. spathulifolia

- Leaf blade long obovate, rarely oblanceolate, 7–10 veins on each side; stamens inserted at the top of corolla tube M. macrophylla