Smilax, Linnaeus, 1753

Sukhramani, Geetika & Choudhary, Ritesh Kumar, 2023, Taxonomic Reconciliation of Smilacaceae in the Indian Subcontinent: Synonymy, Typification, Updated Inventory, and a Vegetative Key for Identification, Phytotaxa 622 (1), pp. 42-62 : 56-57

Vegetative key for Smilax taxa in the Indian subcontinent:

1. Vines with climbing stems; tendrils well developed ..........................................................................................................................2

- Shrubs with erect stems; tendrils none .............................................................................................................................................11

2. Stem and branches granulate-verruculose or rough .........................................................................................................................15

- Stem and branches non-granulate and smooth ...................................................................................................................................3

3. Branches without prickles ................................................................................................................................................................16

- Branches with straight or recurved prickles .......................................................................................................................................4

4. Leaves glaucous beneath ..................................................................................................................................................................24

- Leaves non-glaucous beneath.............................................................................................................................................................5

5. Leaf blades ovate or cordate deltoid with rounded lobes at base and spiny margins............................................................ S. aspera

- Leaf blades not as above.....................................................................................................................................................................6

6. Petiolar wings well developed, more than 5 mm broad ..................................................................................................... S. prolifera

- Petiolar wings weakly developed, 5 mm or less than 5 mm broad ....................................................................................................7

7. Leaf blades cordate to subcordate at base; petiole 3.5–5 cm ................................................................................................ S. wightii

- Leaf base not as above........................................................................................................................................................................8

8. Leaf blade mucronate or with short cusp at apex .............................................................................................................................30

- Leaf apex not as above .......................................................................................................................................................................9

9. Stem angular.....................................................................................................................................................................................34

- Stem terete ........................................................................................................................................................................................10

10. Leaf blades 5-costae, 6–15 cm × 1.5–8 cm broad, caudate at apex; petiole 5–10 mm long ........................................... S. lanceifolia

- Leaf blades 3-costae, 6–11 cm × 1–2 cm broad, acute or cuspidate at apex; petiole 10–25 mm long.......................... S. arisanensis

11. Leaves petiolate................................................................................................................................................................................12

- Leaves sessile ...................................................................................................................................................................................14

12. Leaves non-glaucous beneath; sparsely branched............................................................................................................... S. turbans

- Leaves glaucous beneath; densely branched ...................................................................................................................................13

13. Leaf blades ovate-lanceolate to ovate, contracted or rounded at base, cuspidate at apex .............................................. S. minutiflora

- Leaf blades broadly ovate or orbicular, cuneate or shallowly cordate at base, obtuse at apex .......................................... S. vaginata

14. Stem 2–3 angled; leaves ovate to cordate; stem and branches prickly.................................................................................. S. munita

- Stem 4 or more angled; leaves rhombic-ovate; stem and branches unarmed.................................................................... S. myrtillus

15. Branches slightly zig-zag; leaf blades oblong-lanceolate, cuspidate at apex; petiole 1–2 cm long............................ S. odoratissima

- Branches straight; leaf blades ovate-elliptic, acuminate at apex; petiole 2.5–5 cm long................................................... S. griffithii

16. Leaf blades cuneate or rounded at base............................................................................................................................................17

- Leaf blades cordate or subcordate at base ........................................................................................................................................20

17. Leaves non-glaucous beneath; blades cuneate at base (never rounded)......................................................................... S. megacarpa

- Leaves glaucous beneath; blades cuneate or rounded at base ..........................................................................................................18

18. Stem and branches terete; blades ovate-lanceolate or ovate oblong, 7–16 cm × 2.5–5 cm .................................................. S. glabra

- Stem and branches shallowly angular; blades ovate or narrowly ovate, 3–9 cm × 1.5–4 cm ..........................................................19

19. Leaf papillose; petiolar wings recurved on entire margins, deltoid at apex ................................................ S. elegans subsp. elegans

- Leaf not papillose; petiolar wings not recurved, minutely acute at apex ............................................... S. elegans subsp. osmastonii

20. Leaves glaucous beneath ..................................................................................................................................................................21

- Leaves non-glaucous beneath...........................................................................................................................................................22

21. Petiole 0.6–1.5 cm long; petiolar wings weakly developed, deltoid at apex; stem terete ..................................... S. menispermoidea

- Petiole 3–5 cm long; petiolar wings weakly developed, not deltoid at apex; stem angular........................................ S. pseudochina

22. Stem angular........................................................................................................................................................................... S. bockii

- Stem terete ........................................................................................................................................................................................23

23. Leaf blade 5–13 cm × 1.5–7 cm broad; petiole 0.5–2 cm ............................................................................................... S. polyandra

- Leaf blade 3–15 cm × 1–5 cm broad; petiole 10–25 mm .............................................................................................. S. biumbellata

24. Petiolar wings well developed, more than 5 mm broad ...................................................................................................................25 - Petiolar wings weakly developed, 5 mm or less than 5 mm broad ..................................................................................................28

25. Petiolar wings transversely hastate, gradually narrowed to cuneate base not clasping the branch, deltoid-acute at apex................... ......................................................................................................................................................................................... S. orthoptera

- Petiolar wings broadly ovate, cordate base clasping the branch, acute at apex ...............................................................................26

26. Leaf blades 7–18 cm × 2.5–13 cm broad, contracted or rounded at base, acute or rounded at apex ...............................................27

- Leaf blades 13–25 cm × 8–17 cm broad, rounded or shallowly cordate, acute or acuminate apex with short cusp ............ S. blumei

27. Leaf blades broadly ovate............................................................................................................................................... S. perfoliata *

- Leaf blades more ovate-elliptic ............................................................................................................................................ S. ocreata

28. Stem and branches angular .......................................................................................................................................... S. microphylla

- Stem and branches terete ..................................................................................................................................................................29

29. Branches straight; internodes 1.5–2.5 cm long; petioles 5–7 mm long; leaf blades 2.5–7 cm × 1–3 cm ............................... S. ferox

- Branches zig-zag; internodes 2–7 cm; petioles 10–15 mm long; leaf blades 2–12 cm × 2–8 cm ........................................... S. china

30. Stem angular...................................................................................................................................................................... S. zeylanica

- Stem terete ........................................................................................................................................................................................31

31. Leaf blades ovate-lanceolate or elliptic-oblanceolate or elliptic......................................................................................................32

- Leaf blades broadly ovate or orbicular.............................................................................................................................................33

32. Leaf blades rounded at base ............................................................................................................................................ S. luzonensis

- Leaf blades cuneate at base .............................................................................................................................................. S. davidiana

33. Leaf blades with more than 3 costae ranging from 5–7 ................................................................................................... S. ovalifolia

- Leaf blades with strictly 3 costae ......................................................................................................................................... S. sailenii

34. Stem and branches closely prickly ............................................................................................................................... S. polyacantha

- Stem and branches sparsely prickly .................................................................................................................................................35

35. Branches zig-zag, leaf blades 4–15 cm × 1.8–6 cm, contracted or rounded at base ......................................................... S. quadrata

- Branches straight, leaf blades 9–12 cm × 6–9.5 cm broad, cuneate at base.................................................................. S. hemsleyana

* S. perfoliata and S. ocreata can be distinguished most reliably from the inflorescence i.e., 7–15 umbels in S. perfoliata versus 1–3 umbels in S. ocreata .