Rubus, Linnaeus (1753: 492), Linnaeus, 1753

Beek, Abraham Van De, 2021, Rubi Capenses: a further contribution to the knowledge of the genus Rubus (Rosaceae) in South Africa, Phytotaxa 515 (1), pp. 1-71 : 8-9

Key to the species in the Western Cape and adjacent regions of South Africa

Weber (1973) introduced the term ‘periodical’ (‘periodisch’) for a characteristic form of serrature found in Rubus , and most later authors followed him in this. It means a serrature that increases and decreases like waves with a sharp tip. Good examples are found in two newly described taxa in this paper, namely R. trichogynus A.Beek ( Fig. 17E ) and R. ×fultiformis A.Beek ( Fig. 26D & E ).

‘Flowering branch’ means the branch of the individual inflorescences. ‘Floricane’ is used for the whole stem with several inflorescences, in contrast to the primocane; the primocane is the stem that grows first without flowering; when it flowers, in the next year, it is called ‘floricane’; after flowering and bearing fruits the stem dies. So each plant usually has non-flowering primocanes and flowering floricanes. When collecting specimens, samples from both stems must be taken, because the leaves of the primocane are very characteristic.

1. Primocane and inflorescences with long red bristles ........................................................................................ 18. R. phoenicolasius

- Plant without bristles; primocane with hard prickles and sometimes stipitate glands .......................................................................2

2. Primocane low mounding and soon prostrate; leaves abaxially green...............................................................................................3

- Primocane erect, arching or scrambling; leaves abaxially green, grey or white ................................................................................5

3. Pedicels with numerous stipitate glands...............................................................................................................21. R. macropetalus

- Pedicels eglandular or with some subsessile glands...........................................................................................................................4

4. Serrature rather regular, periodical (see introduction to key); central leaflet of 3-foliolate leaves triangular, deep cordate; prickles on flowering branch weak, 2–3 mm ....................................................................................................................... 20. R. trichogynus

- Serrature very coarse, often almost incised; central leaflet of 3-foliolate leaves ovate or rhombic-obovate, with emarginate or cordate base; prickles on flowering branch strong, 4–6 mm ............................................................................................ 9. R. titanus

5. Plant (almost) sterile...........................................................................................................................................................................6

- Plant fertile .......................................................................................................................................................................................12

6. Leaves pinnate....................................................................................................................................................................................7

- Leaves digitate, often with divided central leaflet..............................................................................................................................8

7. Petals small, much shorter than sepals ........................................................................................................ 38. R. pinnatus × rigidus

- Petals large, longer than sepals..................................................................................................... 37. R. chrysocarpus × trichogynus

8. Leaves abaxially green, almost glabrous........................................................................................................................33. R. ×fultus

- At least apical leaflets abaxially greyish tomentose...........................................................................................................................9

9. Inflorescence with numerous very strong, 8–10 mm long prickles.........................................................36. R. affinis × noli-tangere

- Inflorescence with moderate to rather strong, up to 8 mm long prickles .........................................................................................10

10. Prickles slender, curved or hooked; serrature very sharp serrate with long mucros ..............................................34. R. ×fultiformis

- Prickles compressed, straight or curved; serrature triangular to sharp, often with short mucros.....................................................11

11. Stem with patent hairs; ovaries hairy .............................................................................................................35. R. affinis × ecklonii

- Stem glabrous or with ± appressed hairs; ovaries glabrous or hairy .......................................................................32. R. ×bergianus

12. Inflorescence with only one flower or a few separate in axils of leaves...................................................................... 1. R. rosifolius

- Inflorescence racemose, paniculate or corymbose ...........................................................................................................................13

13. Leaves digitate; fruits shiny black....................................................................................................................................................14

- Leaves pinnate; fruits yellow, orange, red or black..........................................................................................................................23

14. Leaflets divided into narrow segments; petals incised .............................................................................................. 29. R. laciniatus

- Leaflets serrated; petals not incised, sometime with emarginate apex.............................................................................................15

15. Inflorescence paniculate ...................................................................................................................................................................16

- Inflorescence racemose or cymose...................................................................................................................................................18

16. Leaves abaxially densely white tomentose.......................................................................................................................................17

- Leaves abaxially green or apical ones greyish ................................................................................................................ 28. R. affinis

17. Primocane densely pruinose; leaves small; central leaflet 4–9 cm ........................................................................... 31. R. ulmifolius

- Primocane not or slightly pruinose; leaves moderate to large; central leaflet 8–13 cm ..........................................30. R. armeniacus

18. Pedicels with stipitate glands.............................................................................................................................. 25. R. allegheniensis

- Pedicels eglandular or with a few subsessile glands ........................................................................................................................19

19. Leaflets abaxially white- or grey-tomentose, mostly small, 3–7 cm long, obtuse or short-pointed ................................................20

- Leaflets green or slightly greyish beneath, larger, 6–14 cm long; central primocane leaflet acuminate .........................................21

20. Central leaflet 44–53(–65) mm long, with attenuate or rounded base, narrow, obovate or elliptic-obovate, abruptly attenuate into short tip; width–length index 0.45–0.61; length of petiolule 17–30% of leaflet length ...........................................26. R. probabilis

- Central leaflet 57–70 mm long, broad elliptic, with rounded or subcordate base, rather abruptly attenuate into short tip; width– length index 0.62–0.80; length of petiolule 27–43% of leaflet length ......................................................................... 27. R. pascuus

21. Primocane with short hairs, arching; central leaflet elliptic to obovate .....................................................................22. R. originalis

- Primocane (almost) glabrous, suberect; central leaflet ovate to elliptic...........................................................................................22

22. Serrature triangular; central leaflet gradually short acuminate ................................................................................... 24. R. laudatus

- Serrature sharp, narrow; central leaflet rather abruptly and rather long acuminate ...................................................... 23. R. revealii

23. Petals very large, much longer than sepals.............................................................................................................. 17. R. thaumasius

- Petals small, shorter than to hardly longer than sepals.....................................................................................................................24

24. Leaves small, deeply incised, abaxially white tomentose; central leaflet 2.5–3.0(–5) cm long; plants (often much) lower than 1 m ...................................................................................................................................................................................... 16. R. ludwigii

- Leaves larger, serrate, or somewhat incised, abaxially green, grey or white; central leaflet more than 4 cm long; plants usually higher than 1 m .................................................................................................................................................................................25

25. Petals less than 3 mm long .................................................................................................................................... 7. R. cryptopetalus

- Petals more than 3 mm long .............................................................................................................................................................26

26. At least part of leaves abaxially grey or rarely greyish green tomentose.........................................................................................27

- Leaves abaxially green, sometimes with long white hairs on veins.................................................................................................34

27. Primocane with many stipitate glands; inflorescence with few to many stipitate glands ................................................................28

- Primocane without stipitate glands; inflorescence sometimes with some subsessile glands ...........................................................30

28. Suberect plants; leaves shiny................................................................................................................................11. R. chrysocarpus

- Scrambling or high arching plants with prostrate tip; leaves not shiny ...........................................................................................29

29. Central leaflet of pinnate leaves with attenuate to cordate base, ovate, triangular, roundish or (elliptical-)obovate, acute or obtuse, width–length index 0.69–0.96; serrature fine to mediocre, obtuse, shallow, short obtuse periodical, with very short mucros........... ...................................................................................................................................................................................10. R. leptodytus

- Central leaflet with attenuate or sometimes almost rounded, never cordate base (ob-)ovate or elliptical, gradually attenuate in long tip, sometimes lobate, width–length index 0.55–0.69; serrature fine, very sharp, unequal, double, with long (almost) straight mucros ..............................................................................................................................................................................8. R. rigidus

30. Leaves adaxially (almost) glabrous; 1–11 prickles per 5 cm ...........................................................................................................31

- Leaves adaxially pilose; 5–35 prickles per 5 cm ..............................................................................................................................32

31. Leaves abaxially grey tomentose; flowering branch densely hairy.................................................................................9. R. ecklonii

- Leaves abaxially partly greenish; flowering branch thinly appressed hairy ............................................................13. R. cacoeimon

32. Petals very small, long clawed (3–5 mm incl. claw); primocane high arching with tip to soil.......................................15. R. fertilis

- Petals 4–9 mm, short clawed; primocane suberect...........................................................................................................................33

33. Prickles of primocane 20–35 per 5 cm very strong, 8–10 mm long.......................................................................14. R. noli-tangere

- Prickles of primocane 5–15 per 5 cm, moderate, 4–8 mm long.................................................................................... 12. R. mundtii

34. Leaves abaxially with long patent white hairs on veins................................................................................................... 3. R. pappei

- Leaves abaxially glabrous or with some short appressed hairs on the main veins...........................................................................35

35. Primocane densely short hairy....................................................................................................................................... 2. R. pinnatus

- Primocane (almost) glabrous............................................................................................................................................................36

36. Prickles on flowering branch 1–2 mm; pedicels 7–18 mm; leaves 4- to 5-jugate ................................................6. R. leptostelechus

- Prickles on flowering branch 3–5 mm; pedicels 3–14 mm; leaves 2- to 3-jugate ...........................................................................37

37. Stem pruinose; flowering branch hairy, with 7–20 prickles per 5 cm; sepals greyish green to grey ...................................5. R. anas

- Stem epruinose, flowering branch glabrous, with 2–7 prickles per 5 cm; sepals green to greyish green......................4. R. glabrior

Figures

FIGURE 17. Rubus trichogynus. A. Holotype, primocane. B. Holotype, inflorescence. C. Primocane. D. Primocane. E. Leaf, abaxially. F. Flowering branch. G. Inflorescence. H. Pedicel and young fruit. I. Flowers. Photographs: A. van de Beek.

FIGURE 26. Rubus ×fultiformis. A. Holotype, primocane. B. Holotype, inflorescence. C. Primocane. D. Leaf abaxially. E. Narrow leaf. F. Flowering branch. Photographs: A. van de Beek.