Desmodieae (Bentham) Hutchinson

Jiang, Kai-Wen, Song, Zhu-Qiu, Pan, Bo, Zhao, Xue-Li, Li, Shi-Jin, Tu, Tie-Yao & Gong, Yan-Xiong, 2024, Hegnera obcordata (Fabaceae: Desmodieae), a newly recorded genus and species for the flora of China, Phytotaxa 644 (2), pp. 145-153 : 150-151

Key to Chinese genera of Desmodieae

1. Hooked hairs absent; pods 1-seeded...................................................................................................................................................2

-. Hooked hairs generally present; pods generally more than 1-seeded, rarely 1-seeded......................................................................4

2. Lateral veins of leaflets straight and extending to margin; stipules large, ovate; flowers small, axillary....... Kummerowia Schindl.

-. Lateral veins of leaflets arcuate, looped within margin; stipules small, subulated; flowers large, arranged in inflorescence...........3

3. Bracts 1-flowered; pedicels articulate below calyx; keel petals falcate, acute at apex .................................... Campylotropis Bunge

-. Bracts 2-flowered; pedicels not articulate; keel petals strict, obtuse at apex ......................................................... Lespedeza Michx.

4. Branch nodes with 3-fid, hard spines ................................................................................................................ Trifidacanthus Merr.

-. Branch nodes without spines ..............................................................................................................................................................5

5. Calyx glumaceous, lobes dry and hard, striate with strong nerves proliferating from base................................... Alysicarpus Desv.

-. Calyx not glumaceous, lobes herbaceous, not striate.........................................................................................................................6

6. Pods inflated, not jointed............................................................................................................ Pycnospora R. Br. ex Wight & Arn.

-. Pods compressed, jointed ...................................................................................................................................................................7

7. Leaflets (or at least the terminal leaflet) wider than long...................................................................................................................8

-. Leaflets generally longer than wide .................................................................................................................................................11

8. Plant climbing or creeping....................................................................................................................................... Hegnera Schindl.

-. Plant erect or diffuse, never climbing or creeping..............................................................................................................................9

9. Calyx accrescent, enveloping the plicate-retrofracted loment .................................................................................. Christa Moench

-. Calyx not accrescent, loments not plicate-retrofracted ....................................................................................................................10

10. Flowers densely arranged, 2 per node; pedicels hooked-inflexed at apex and inverting flowers; loments 1–2-jointed...................... .................................................................................................................................................................................... Mecopus Benn.

-. Flowers sparsely arranged, 2–5 per node; pedicels not as above; loments 4–6-jointed....................................................................... ...................................................................................................................................................... Huangtcia H. Ohashi & K. Ohashi

11. Loments persistently plicate-retrofracted within the 4-lobed calyx; flowers 2(–3) per node ..........................................................12

-. Loments not plicate-retrofracted, or if so than calyx 5-lobed and flowers 2–8 per node.................................................................13

12. Joints of loment connected along ventral suture ...................................................................................................... Uraria Desv. p.p.

-. Joints of loment connected at center of joint........................................................................................................ Urariopsis Schindl.

13. Flowers 1 per node; bracteoles well-developed ..................................................................... Dendrolobium (Wight & Arn.) Benth.

-. Flowers 2–several per node; bracteoles small or absent ..................................................................................................................14

14. Primary bracts foliaceous ........................................................................................................................................ Phyllodium Desv.

-. Primary bracts not as above..............................................................................................................................................................15

15. Leaflets 3, almost digitately arranged; stipules unite, 3-fid ................................................................... Aphyllodium (DC.) Gagnep.

-. Leaflets 1 or 3, pinnately arranged; stipules free, not 3-fid..............................................................................................................16

16. Loments distinctly stipitate, lower suture (dorsal suture) deeply incised, isthmus no more than 1/5 as broad as legume ..............17

-. Loments not stipitate or very shortly stipitate, constricted on both sutures or if lower suture deeply incised, then isthmus more than 1/5 as broad as loment ......................................................................................................................................................................18

17. Perennial herbs; articles obliquely triangular or slightly broadly subobovate ..................................................................................... ................................................................................................................................................. Hylodesmum H. Ohashi & R. R. Mill

-. Shrubs; articles nearly semicircular................................................................................................ Tateishia H. Ohashi & K. Ohashi

18. Petioles distinctly winged.................................................................................................................................................................19

-. Petioles not winged...........................................................................................................................................................................20

19. Leaves 1-foliolate; flowers reddish purple .......................................................................................................... Tadehagi H. Ohashi

-. Leaves 3-foliolate; flowers white to cream .............................................................................................................. Ohwia H. Ohashi

20. Fruits not jointed, i.e. not break up into articles under natural conditions, dehiscent along lower suture when mature .................21

-. Fruits distinctly jointed, i.e. break up into articles under natural conditions, generally indehiscent along suture(s) ......................23

21. Seeds not conspicuously arillate; fruits with sutures almost straight; leaves with 3 well-developed leaflets with lateral veins extending to margin................................................................................................................................. Pseudarthria Wight & Arn.

-. Seeds conspicuously arillate; fruits with lower suture undulate; leaves with lateral leaflets reduced or absent, lateral veins looped within margin....................................................................................................................................................................................22

22. Erect shrubs ........................................................................................................................................................ Codariocalyx Hassk.

-. Prostrate or erect herbs ........................................................................................................................................ Leptodesmia Benth.

23. Stamens monadelphous with vexillary filament connate to other filaments....................................................................................24

-. Stamens diadelphous with vexillary filament free from other filaments .........................................................................................27

24. Prostrate or ± scandent subshrubs; flowers 2 per node; adaxial surface of leaflet with a silvery plaque along the midvein............... ............................................................................................................. Desmodium Desv. p.p. [ Desmodium uncinatum (Jacq.) DC. ]

-. Erect shrubs or small trees; flowers 3–7 per node; adaxial surface of leaflet without plaque .........................................................25

25. Bracteoles absent ......................................................................................................................................................... Ototropis Nees

-. Bracteoles present.............................................................................................................................................................................26

26. Loments usually with hooked hairs, rarely glabrous (not found in China) .................................... Puhuaea H. Ohashi & K. Ohashi

-. Loments without hooked hairs, sericeous, pubescent, puberulent or glabrous .................................................................................... ..................................................................................................................................................... Sunhangia H. Ohashi & K. Ohashi

27. Loments linear, articles linear, oblong, or oblong-linear to narrowly obovoid, ca. 3 × as long as wide or more ............................28

-. Loments narrowly oblong, articles often orbicular, nearly oblong, or nearly quadrate, nearly as long as wide or slightly longer.29

28. Stipules deciduous, free, triangular ................................................................................................ Sohmaea H. Ohashi & K. Ohashi

-. Stipules persistent, connate, leafy and amplexicaul ............................................................................................................................. ................................................................................................ Desmodium Desv. p.p. [ Desmodium scorpiurus (Sw.) Desv. ex DC. ]

29. Seeds ± detached from articles by isthmus when mature................................................................................................ Grona Lour.

-. Loments not dehiscent along isthmus, seeds persistent within articles............................................................................................30

30. Leaves generally 1-foliolate, less frequently mixed with 3-foliolate leaves ....................................................................................31

-. Leaves generally 3-foliolate, less frequently mixed with 1-foliolate leaves ....................................................................................33

31. Flowers crowded on peduncles; leaflets yellowish-brown velutinous on both surfaces.............. Polhillides H. Ohashi & K. Ohashi

-. Flowers lax, scattered on peduncles; leaflets adaxially glabrous, abaxially pubescent or villous ...................................................32

32. Pedicels ca. 12 mm; loments subglabrous, glabrescent........................................................................................................................ .................................................................................. Uraria Desv. p.p. [ Uraria oblonga (Wall. ex Benth.) H. Ohashi & K. Ohashi ]

-. Pedicels 2–5 mm; loments covered with hooked hairs ................................................................................... Pleurolobus J. St. -Hil.

33. Stems angular and deeply sulcate................................................................................................ Bouffordia H. Ohashi & K. Ohashi

-. Stems not as above .......................................................................................................................................... Desmodium Desv. p.p.