Polygonum

Keskin, Mustafa & Severoğlu, Zeki, 2022, Novelties in the genus Polygonum (Polygonaceae) in Turkey, Phytotaxa 538 (2), pp. 113-123 : 120-121

A diagnostic key to of the Polygonum species occurring in Turkey follow.

1. Annuals with slender root system.......................................................................................................................................................2

- Perennials with thick and woody root system ..................................................................................................................................17

2. Achenes longer than tepals; shore plants.................................................................................................................... P. mesembricum

- Achenes at most slightly longer than tepals; usually land plants .......................................................................................................3

3. Tepals 3–4 mm long; leaves 12–45 mm long, quickly deciduous...................................................................................... P. bellardii

- Tepals usually shorter than 2.5 mm long; leaves average 5–25 mm long not quickly deciduous......................................................4

4. Ochrea without veins..........................................................................................................................................................................5

- Ochrea veined.....................................................................................................................................................................................6

5. Leaves revolute, obovate; plants usually erect......................................................................................................... P. cappodocicum

- Leaves flat, linear to lanceolate; plants prostrate ..................................................................................................... P. polycnemoides

6. Tepal pouched at base....................................................................................................................................................... P. buxiforme

- Tepal smooth, not pouched.................................................................................................................................................................7

7. Inflorescence short and congested, spike like; mostly growing in dunes or fine-grained soil........................................ P. arenarium

- Inflorescence long and loosely arranged; mostly growing in land.....................................................................................................8

8. Most of middle leaves up to 2 mm wide ............................................................................................................................................9

- Most middle leaves wider than 2 mm ...............................................................................................................................................14

9. Internodes very short and covered by leaf and ochrea; achenes usually black ......................................................... P. rottboellioides

- Internodes not covered by leaf and ochrea; achenes brown to dark brown......................................................................................10

10. Flowers solitary in axils of scarious bracts; leaves subulate to filiform, 0.5 mm wide................................................ P. salsugineum

- Flowers 1–3 in axils of leaflike bracts; leaves 0.8–2.2 mm wide.....................................................................................................11

11. Short and sterile shoots present; the edges of the leaves here are folded longitudinally; fruiting tepals suburceolate to urceolate.... ............................................................................................................................................................................................ P. urnigera

- Sterile shoots absent; leaves flat or rarely somewhat folded; fruiting tepals at most suburceolate (some perennials e.g. P. karacae ) but usually adjacent at the tip or open..............................................................................................................................................12

12. Longest pedicel 2.0– 2.5 mm, longer than tepals ............................................................................................................ P. pulchellum

- Longest pedicel usually shorter than 2 mm, shorter than tepals.......................................................................................................13

13. Tepal tube about as long as the lobes; ochrea 3–8 mm long ......................................................................................... P. arenastrum

- Tepal tube much shorter than the lobes; ochrea 6–12 mm long ...................................................................................... P. rurivagum

14. Inflorescence usually 4–6 flowered; veins usually not branched on tepals at fruiting time.............................................................15

- Inflorescence usually 1–3 flowered; veins branched on tepals at fruiting time ...............................................................................16

15. Leaves fresh green; ochrea 8–10 mm; pedicels 1.5–3.0 mm; achenes tuberculate........................................................... P. aviculare

- Leaves bluish-green; ochrea 4–8 mm; pedicels 1–2 mm; achenes smooth................................................................ P. argyrocoleon

16. Leaves 25–40 mm; ochrea 7–9 mm; achenes 2–2.5 mm ..................................................................................................... P. patulum

- Leaves 4–35 mm; ochrea 4–8 mm; achenes 1.2–1.8 mm ................................................................................................ P. neglectum

17. Shore plants; ochrea longer than nodes .......................................................................................................................... P. maritimum

- Land plants; ochrea usually shorter than nodes.................................................................……….……………….……….……... 18

18. Ochrea 3–nerved, entirely membranous and equal or longer than internodes ................................................................. P. cognatum

- Ochrea (5–)10–nerved, tube brownish, shorter than internodes.......................................................................................................19

19. Leaf-like bracts absent towards the top............................................................................................................................... P. karacae

- Bracts similar to leaves but shorter ..................................................................................................................................................20

20. Ochrea and leaves overlapping; the plant looks whitish due to hyaline ochrea; leaves mucronate; tepals 1–1.5 mm long ................ ................................................................................................................................................................................. P. paronychioides

- Not as above .....................................................................................................................................................................................21

21. Leaves quickly deciduous at flowering time; plant prostrate with some shoots erect ............................................... P. e quisetiforme

- Leaves not deciduous at flowering time; plants usually strict..........................................................................................................22

22. Prostrate or stoloniferous plants with 40–150 cm tall; inflorescence present on short and third shoots ........................... P. longipes

- Plants suffrutescent with hard woody stocks; inflorescence usually on main shoots ......................................................................23

23. Tepals shorter than 2.5 mm long ......................................................................................................................................................24

- Tepals longer than 2.5 mm long .......................................................................................................................................................27

24. Stem and leaves ashy–glaucous; tepal with sparse pink glands near the base ............................................................. P. praelongum

- Stem and leaves green; tepal unglandular ........................................................................................................................................25

25. Inflorescence a lax, elongated spike; leaves overlapping at the base; tepals 1.7–2.0 mm long.................................... P. s alebrosum

- Inflorescences densed, like a head or congested spike; leaves loosely not overlapping; tepal 2.0– 2.5 mm long............................26

26. Stem 15–70 cm; 2–4 flowers in fascicle; pedicels 1–3 mm ................................................................................................ P. melihae

- Stem 21–32 cm; 5–7 flowers in fascicle; pedicels 3–5 mm ............................................................................................ P. afyonicum

27. Leaves pustulate; achenes longer than tepals .............................................................................................................. P. istanbulicum

- Leaves smooth; achenes shorter or at most equal to tepals ..............................................................................................................28

28. Flowers sessile or rarely with at most 1.5 mm pedicel..................................................................................................... P. sivasicum

- Flowers obviously pedicellate ..........................................................................................................................................................29

29. Leaves usually 10 mm wide and strongly revolute at the margin .................................................................................... P. luzuloides

- Leaves 4–5 mm wide on average and flat or slightly revolute margin.............................................................................................30

30. Ochrea not veined; tepals 3.5–4.5 mm long; achenes equal to slightly longer than tepals ............................................ P. ekimianum

- Ochrea strongly veined; tepals 2.5–3.5 mm long; achenes slightly shorter than tepals...................................................................31

31. Leaves usually undulate margin; achenes brown ......................................................................................................... P. samsunicum

- Leaves flat margin; achenes blackish .................................................................................................................................. P. setosum