Diplazium, Swartz, 1801

Pongkai, Puttamon, Zhang, Li-Bing, Boonkerd, Thaweesakdi & Pollawatn, Rossarin, 2023, Revision of the fern genus Diplazium (Polypodiales: Athyriaceae) in Thailand, Phytotaxa 631 (1), pp. 1-69 : 8-9

Key to the species of Diplazium in Thailand

1a Fronds simple .....................................................................................................................................................................................2

1b Fronds compound ...............................................................................................................................................................................3

2a Lamina cordate; scale margins entire ...................................................................................................................... 4. D. cordifolium

2b Lamina oblong; scale margins toothed................................................................................................................. 27. D. subserratum

3a Fronds unipinnate ...............................................................................................................................................................................4

3b Fronds bipinnate ...............................................................................................................................................................................23

4a Rhizome creeping...............................................................................................................................................................................5

4b Rhizome erect.....................................................................................................................................................................................8

5a Upper pinnae not reduced; terminal pinna distinct…………………………………………….........................................................6

5b Upper pinnae gradually reduced; terminal pinna not distinct……………………………........ ........................................................7

6a Terminal pinna simple ................................................................................................................................................ 6. D. donianum

6b Terminal pinna pinnatifid .................................................................................................................................... 29. D. thailandicum

7a Veinlets simple or once forked, 3–4 pairs; sori cresentic, 2–3 mm long.......................................................................... 18. D. petrii

7b Veinlets all free, 4–5 pairs; sori elongate along vein, 4–5 mm long ................................................................... 13. D. mettenianum

8a Scales entire........................................................................................................................................................................................9

8b Scales toothed...................................................................................................................................................................................12

9a Terminal pinna not distinct...............................................................................................................................................................10

9b Terminal pinna distinct .....................................................................................................................................................................19

10a Stipes and rachis tomentose................................................................................................................................... 30. D. tomentosum

10b Stipes and rachis glabrous ................................................................................................................................................................11

11a Auricle at basiscopic base of pinnule distinct; pinnae-stalks 4–5 mm long…..…….……..……................................ 14. D. mixtum

11b Auricle not distinct; pinnae-stalks less than 3 mm long............................................................................................... 9. D. holttumii

12a Terminal pinna distinct .....................................................................................................................................................................13

12b Terminal pinna not distinct...............................................................................................................................................................15

13a Lateral pinnae 10–15 pairs; terminal pinna subdeltoid, unlike lateral pinnae; lobed at margin.......................................................14

13b Lateral pinnae 3–5 pairs; terminal pinna similar to lateral one, entire at margin.................................................... 1. D. bantamense

14b Veins anastomosing; pinnae subentire to crenate at margin; gemmae absent .................................................... 12. D. megaphyllum

14b Veins free; pinnae serrate at margin; gemmae usually present between rachis and pinnae .................................... 22. D. proliferum

15a Veins all free .....................................................................................................................................................................................16

15b Veins anastomosing .................................................................................................................................................. 7. D. esculentum

16a Pinnae subentire or crenate at margin; auricle present at acroscopic base.......................................................................................17

16b Pinnae lobed at margin; auricle absent…….....................................................................................................................................18

17a Veinlets 1–2 pairs; pinnules 2.5–4 cm broad; distinctly auricled at base................................................................ 19. D. phanerotis

17b Veinlets 3–4 pairs; pinnules 1–1.5 cm broad; moderately auricled at base ............................................................ 28. D. sylvaticum

1 ∗ Following floristic format, references like this are not listed in References but can be found in Tropicos or IPNI.

18a Pinnae suddenly becoming smaller upwards, stalks up to 2 cm long ....................................................................... 23. D. siamense

18b Pinnae gradually becoming smaller upwards, stalks less than 0.5 cm long........................................................ 25. D. sorzogonense

19a Lateral pinnae more than 10 pairs; pinnae 2 cm wide; veins all free ...............................................................................................20

19b Lateral pinnae less than 7 pairs; pinnae more than 3 cm wide; veins anastomosing .......................................................................21

20a Veinlets 1 pairs, stalks 1–2 mm long.......................................................................................................................... 16. D. pallidum

20b Veinlets more than 1 pairs, stalks more than 3 mm long...................................................................................... 26. D. subintegrum

21a Pinnae ovate-lanceolate, long acuminate at apex, obtuse at base; gemmae usually present at junction between rachis and base of pinnae ...................................................................................................................................................................... 4. D. cordifolium

21b Pinnae oblong, acuminate at apex, acute at base; gemmae absent………………….…..................................................................22

22a Fronds less than 40 cm long; pinnae 2–4 pairs...................................................................................................... 8. D. fraxinifolium

22b Fronds up to 60 cm long; pinnae 4–7 pairs ........................................................................................................ 31. D. xiphophyllum

23a Rhizome creeping ............................................................................................................................................................................25

23b Rhizome erect or ascending..............................................................................................................................................................27

24a Scales with black margin....................................................................................................................................... 3. D. conterminum

24b Scales concolorous ...........................................................................................................................................................................25

25a Sori curved or cresentic usually lie on acroscopic veinlets of vein group .......................................................................................26

25b Sori oblong, usually lie on all veinlets .................................................................................................................. 21. D. procumbens

26a Sori submarginal, 2–3.5 mm long .................................................................................................................................... 18. D. petrii

26b Sori close to costule, 3–5 mm long ..................................................................................................................... 11. D. leptophyllum

27a Scales with black margins ...............................................................................................................................................................28

27b Scales with no black margins ..........................................................................................................................................................33

28a Sori oblong, usually less than 3 mm long.........................................................................................................................................29

28b Sori linear, usually more than 5 mm long .......................................................................................................................................30

29a Sori close to midrib of lobe ................................................................................................................................ 19. D. polypodioides

29b Sori medial between margin and midrib of lobe ................................................................................................... 10. D. kappanense

30a Veins free; pinnules lobed at margin ...............................................................................................................................................31

30b Veins anastomosing; pinnules subentire at margin................................................................................................... 7. D. esculentum

31a Pinnule sessile, base subtruncate to truncate....................................................................................................................................32

31b Pinnules stalked, base minutely cordate...................................................................................................................... 5. D. dilatatum

32a Pinnules crenate to lobe at margin, apexlong-acuminate ................................................................................. 24. D. simplicivenium

32b Pinnules subentire to serrate at margin, apex acute to acuminate ................................................................................ 17. D. petelotii

33a Pinnae and pinnule subopposite to opposite; sori close to costule.................................................................................. 2. D. bellum

33b Pinnae and pinnule alternate; sori not close to costule............................................................................................ 15. D. muricatum