Typhonium, Schott, 1829

Van, Hong Thien, Le, Van Son, Nguyen-Phi, Nga, Nguyen, Quoc Dat, Nguyen, Tran Quoc Trung, Nguyen, Hieu Cuong & Luu, Hong Truong, 2021, A new species and a new record of Typhonium (Araceae) from southern Vietnam, Phytotaxa 527 (3), pp. 201-208 : 206-207

Key to the 19 presently known Vietnamese species of Typhonium

Updated from Van et al. (2017).

1. Leaves perfectly trifoliolate........................................................................................................................................... T. thatsonense

- Not as above .......................................................................................................................................................................................2

2. Sterile interstice of spadix entirely covered with staminodes ..................................................................................... T. flagelliforme

- Only base of sterile interstice of spadix covered with staminodes.....................................................................................................3

3. Spathe limb thin, lanceolate, elongate-triangular...............................................................................................................................4

- Spathe limb thick, ovate to ovate-triangular.....................................................................................................................................14

4. Leaves fully pedate with 5 or 7 leaflets..............................................................................................................................................5

- Leaves entire and/or 3-lobed ..............................................................................................................................................................8

5. Leaves with 7 leaflets, leaf lobes linear to or linear-lanceolate............................................................................................. T. lineare

- Leaves with 5 leaflets, leaf lobes ovate, elliptic to elliptic-lanceolate ...............................................................................................6

6. Spadix much longer than spathe.................................................................................................................................... T. vermiforme

- Spadix almost as long as spathe .........................................................................................................................................................7

7. Ovaries obovoid; stigmas light yellow to white; staminodes subulate, with acuminate apices ................................... T. dongnaiense

- Ovaries elongate or lageniform; stigmas red; staminodes elongate-clavate, with dilated and flattened apices........... T. bachmaense

8. Spadix longer than spathe...................................................................................................................................................................9

- Spadix as long as or shorter than spathe...........................................................................................................................................12

9. Spathe limb corrugated.....................................................................................................................................................................10

- Not as above .....................................................................................................................................................................................11

10. Staminodes folded 180 o apically .............................................................................................................................. T. phuocbinhense

- Staminodes straight up to parallel to axis...................................................................................................................... T. corrugatum

11. Male zone cylindrical, staminodes cylindrical to conical ........................................................................................ T. khonkaenensis

- Male zone subglobose, staminodes clavate ..................................................................................................................... T. acetocella

12. Leaves entire....................................................................................................................................................................... T. laoticum

- Leaves incompletely trifoliolate .......................................................................................................................................................13

13. Stigma funnel shaped and lobed............................................................................................................................. T. stigmatilobatum

- Stigma disciform and unlobed............................................................................................................................................... T. huense

14. Spathe limb very strongly circinnately recoiled over the entire length......................................................................... T. circinnatum

- Not as above .....................................................................................................................................................................................15

15. Staminodes <3 mm long..................................................................................................................................................................16

- Staminodes> 5 mm long..................................................................................................................................................................17

16. Spathe 14–30 cm long, thecae opening by small pores....................................................................................................... T. hayatae

- Spathe 4.5–5.0 cm long, thecae opening by elongate slits .............................................................................. T. vietnamense sp. nov.

17. Staminodes subulate .............................................................................................................................................................. T. blumei

- Staminodes filiform..........................................................................................................................................................................18

18. Staminodes curly ............................................................................................................................................................. T. trilobatum

- Staminodes not curly .................................................................................................................................................... T. penicillatum