Calanthe, R. Brown, 1821

Identification key to the species belonging to Sect. Calanthe View in CoL –– It follows:

1. Leaves deciduous in dry season; inflorescence (including rachis, bracts, and flowers) densely villous; column with a distinct column foot; lip adnate to column foot ................................................................................................................................... C. labrosa

- Leaves not deciduous; inflorescence glabrous or puberulent; column without a column foot; lip adnate to column wings or adnate to base of column................................................................................................................................................................................2

2. Floral bracts caducous; rostellum unlobed.........................................................................................................................................3

- Floral bracts persistent; rostellum 2- or 3-lobed.................................................................................................................................8

3. Lip similar to petals, spurless .................................................................................................................................... C. actinomorpha

- Lip different from petals, spurred at base...........................................................................................................................................4

4. Flowers white ............................................................................................................................................................... C. angustifolia

- Flowers yellow...................................................................................................................................................................................5

5. Lip obscurely 3-lobed; lateral lobes very small, to 1 mm, sometimes inconspicuous ................................................... C. lyroglossa

- Lip distinctly 3-lobed; lateral lobes relatively large, 2–5 mm ............................................................................................................6

6. Spur cylindric; lip adnate to base of column wings; column slender, ca. 12 mm. .......................................................... C. densiflora

- Spur clavate; lip adnate to entire length of column wings; column thick, 5–7 mm ...........................................................................7

7. Leaves narrowly elliptic; lip with 2 triangular lamellae at base of disk..... C. clavata - Leaves oblong-elliptic to oblanceolate; lip with 2 lunar calli between lateral lobes of disk ................................................................................................................ C. speciosa

8. Lip spurless........................................................................................................................................................................................ 9

- Lip spurred; Lip unlobed; Lip margin fimbriate .................................................................................................................. C. alpina

9. Flowers small; sepals to 7 mm ...................................................................................................................................... C. tsoongiana

- Flowers large; sepals 10–20 mm ......................................................................................................................................................10

10. Lip clawed at base, claw forming a shallow sac at base .................................................................................................. C. sacculata

- Lip not clawed..................................................................................................................................................................................11

11. Lip with 3–5 crested lamellae or short-crests on disk......................................................................................................................12

- Lip without lamellae or calli on disk................................................................................................................................ C. ecarinata

12. Flowers pale yellow, with reddish brown lip.................................................................................................................. C. tricarinata

- Flowers pale yellow, with white lip................................................................................................................................. C. wuxiensis