Curcuma subgenus Ecomata

S., Saensouk, T., Boonma & Saensouk, P., 2022, Curcuma achrae (Zingiberaceae), a new species from Central Thailand, Rheedea 32 (1), pp. 30-45 : 42-44

Key to all species of Curcuma subgenus Ecomata

1. Corolla tube longer than bracts; petiole very distinct from leaf blade............. C. supraneeana

1. Corolla tube shorter than bracts; leaf-blade tapering into the petiole ............................... 2

2. Anther spurs filamentous or < 2 mm long .... 3

2. Anther spurs conical or cylindrical or> 2 mm long .............................................................. 10

3. Staminodes with purple colour .................... 4

3. Staminodes without purple colour ............... 5

4. Inflorescence terminal; staminodes white with dark purple at apex ....................... C. pierreana

4. Inflorescence lateral; staminodes light yellow to white with a dark purple patch at base ...... ................................................... C. pambrosima

5. Leaves puberulous on both surfaces ............... .............................................. C. chantaranothaii

5. Leaves adaxially glabrous or glabrous on both surfaces .......................................................... 6

6. Staminodes yellow-orange with light yellow at base .............................................. C. vitellina

6. Staminodes white, or with yellow in the centre or at the apex ................................................ 7

7. Rhizome crawling; leaf base attenuate ........... .............................................. C. cochinchinensis

7. Rhizome ovoid; leaf base oblique, rounded to sub-cordate .................................................... 8

8. Calyx pale purple, puberulent; filament> 5 mm long ................................................... C. pitukii

8. Calyx white, glabrous; filament < 5 mm long ........................................................................ 9

9. Anther crest pure white, apex rounded, 1.5–2 mm long .......................................... C. eburnea

9. Anther crest yellow, apex obtuse, 1.0– 1.5 mm long ..................................................... C. arida

10. Inflorescence terminal ................................. 11

10. Inflorescence lateral..................................... 22

11. Leaves adaxially glabrous ............................ 12

11. Leaves adaxially with hairy along the veins or pubescent ..................................................... 17

12. Staminodes yellow or light orange; leaves abaxially glabrous ........................................ 13

12. Staminodes white; leaves abaxially pubescent ...................................................................... 16

13. Leaf adaxially usually green with red patch along the midrib .......................................... 14

13. Leaf adaxially green without red patch along the midrib .................................................... 15

14. Flowers opened-form; peduncle < 10 cm long ....................................................... C. siamensis

14. Flowers closed-form; peduncle> 10 cm long ..................................................... C. stolonifera

15. Staminodes rhomboid, with dark red dot at the base ................................................... C. rhomba

15. Staminodes asymmetrical trullate to ovate, without red dot at the base ......... C. rangsimae

16. Labellum diamond-shaped, white with a yellow patch in centre and red spots at the base, white with dark purple spots at base .............. ..................................................... C. peramoena

16. Labellum suborbicular, white with two deep orange bands at the centre with deep purple lines at the base ................................. C. woodii

17. Corolla lobes whitish-green to pale green; leaf base cuneate to attenuate .................... C. putii

17. Corolla lobes pink, red or purple; leaf base oblique, rounded or cordate ....................... 18

18. Staminodes lower half red to dark red, upper half orange-yellow ...................................... 19

18. Staminodes pale yellow to yellow .............. 20

19. Inflorescence almost sessile with peduncles c. 1.5 cm long; bracts light green with more or less reddish tinge and prominent veins; Labellum yellowish orange with reddish to purple margins ................................. C. bicolor

19. Inflorescence with longer peduncles to 13 cm long; bracts white, pink to dark red; labellum bright orange with various degrees of red ornamentation ............................... C. flammea

20. Spike> 8 cm long; staminodes pale yellow; corolla lobes white to pale yellow .................. .................................................... C. cinnabarina

20. Spike < 8 cm long; staminodes yellow; corolla lobes red ....................................................... 21

21. Anther spurs c. 2 mm long; bracts pubescent on both surfaces........................... C. stenochila

21. Anther spurs c. 5 mm long; bracts glabrous on both surfaces ............................... C. kayahensis

22. Staminodes purple or with purple at base .. 23

22. Staminodes white or yellow or orange ...... 25

23. Leaf base cuneate; labellum pale pink to dark purple with yellow median band .. C. ecomata

23. Leaf base cordate or rounded; labellum white with yellow or light orange........................ 24

24. Labellum apex strongly recurved with hornlike lobes, light orange with the deep orange line up; staminodes bright orange with dark purple tinge at base .................... C. corniculata

24. Labellum apex curved inward, white with yellow margins, and golden yellow line up; staminodes lower half white, upper half golden yellow, and a purple patch at base..... C. glans

25. Labellum yellow or orange ........................ 26

25. Labellum white or cream white with a yellow median band ................................................ 30

26. Anther almost straight in the side view; staminodes golden yellow, gradually fades to pale yellow at base, with reddish V-shaped or triangular patch at base ..................... C. achrae

26. Anther L-shape; staminodes without reddish patch at base as above.................................. 27

27. Leaves base cuneate; sheath and petiole pubescent ...................................... C. flaviflora

27. Leaves base obtuse or rounded to cordate; sheath and petiole glabrous......................... 28

28. Epigynous glands c. 15 mm long; anther thecae 3–4 mm long ................................ C. xanthella

28. Epigynous glands 4–6 mm long; anther thecae 6–7 mm long ............................................... 29

29. Anther crest apex emarginate; long peduncle; bract with various degree of red tinge ................................................................ C. sahuynhensis

29. Anther crest apex obtuse to rounded; short peduncle; bract green ........................ C. aruna

30. Leaves adaxially green with red patch along the midrib .................................................... 31

30. Leaves adaxially green without red patch along the midrib .................................................... 32

31. Anther almost straight in side view ............... .......................................................... C. candida

31. Anther L-shaped (obtuse angle) in side view ...................................................... C. newmanii

32. Bract green; labellum white, with yellow median band ................................. C. singularis

32. Bracts cream white at the base with increasing red tinge towards apex and margins; labellum cream white, sometimes pale pinkish basally, with deep purple-red or dark red bands placed next to the yellow median band ....... C. tongii