Rubus pinnatus × rigidus

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 : 65-67

38. Rubus pinnatus × rigidus ?

A large bush of a hybrid bramble was found along the R 44 near Arabella Gholf Estate between Kleinmond and Fisherhaven. It grows together with R. pinnatus , and this is obviously one of the parents. Because of the abaxially greyish leaves it may be supposed that the other parent is one of Rubus ser. Rigidi or R. ser. Scleri . Because of the presence of some short stipitate glands, R. rigidus , which grows not far away at Grabouw, might be considered as the other parent.

If one keeps only to the inflorescences it could be even considered that the plants along the R 44 are identical with the type of R. rigidus . They have, however, stronger prickles, more irregular inflorescences and broader leaflets; the primocane and its leaves are totally different. For clarity a full description is given.

Primocane ( Figs 30A–C ) high arching, (bluntly) angular, diam. 4–9 mm, with dense short stellate hairs; prickles 4–10(–15) per 5 cm, somewhat unequal, from 3–5 mm wide base compressed, declining or curved, sometimes geniculate, up to 7 mm long; stipules 8–15 mm, linear or (ovate-)lanceolate, hairy, grey or greenish. Leaves pinnate 5-foliolate, basal leaflets sometimes pedately divided, adaxially glabrous, abaxially ( Figs 30D–E ) grey or white short tomentose or sometimes basal ones green; serrature fine, or rarely at some leaves somewhat deeper, short periodical, with straight dents with short or rather long mucros; petiole 4–6 cm long, with 6–11 curved prickles, short tomentose; central leaflet 42–71 mm long, (ob-)ovate, rhombic or elliptical, with rounded or slightly emarginated base, rather abruptly or gradually attenuate into short tip, width–length index 0.61–0.84, length of petiolule 28–46% of length of leaflet; petiolule between lowest yokes 3.5–6.0 cm; petiolule of lowest leaflets 5–9 mm. Flowering branch ( Figs 30F–G ) (obtuse to furrowed) angular, with dense short stellate hairs; prickles 0–10 per 5 cm, unequal, from 2–4 mm broad base compressed, declined and curved or hooked, up to 3–6 mm long. Leaves pinnate 3-foliolate or 5-foliolate, the uppermost often simple; central leaflet of 5-foliolate leaves 54–78(–93) mm long, rhombic or usually obovate, with attenuate, rounded or slightly emarginate base, rather abruptly or gradually attenuate into short tip, width–length index 0.63–0.73, length of petiolule 12–26% of length of leaflet; central leaflet of 3-foliolate leaves 52–63 mm long, ovate or elliptical with rounded or subemarginate base, width–length index 0.70–0.73, length of leaflet 33–43% of length of leaflet. Inflorescence ( Figs 30H–J ) with few axillary branches and short cylindrical tip, with dense stellate rather short to long hairs, with some fine patent or declined prickles, on basal part of axis often somewhat stronger prickles; pedicels 1–6 mm, densely tomentose and hairy, unarmed, sometimes with scattered very short stipitate gland. Flowers: sepals narrow, long pointed, 2–3 × 5–10 mm, patent to erect, densely grey tomentose and hairy, eglandular or with few short stipitate glands, unarmed; petals ( Fig. 30K ) (light) pink, obovate, 3–6 mm; stamens shorter than styles; anthers glabrous; styles red; ovaries glabrous or at tip with some short stellate hairs; receptacle short hairy. Sterile.

Specimens:— SOUTH AFRICA. Western Cape: Kleinmond, Arabella at Road 44, 22 March 2017, Manning & Sochor RSA 27/17 (‘ R. rigidus’) ( NBG); Kleinmond, R 44, 1 km before the R 43, right side of the road, 24 February 2018, Beek 2018.14 ( L); Kleinmond, road to Hermanus, short before the end of the R 44 on the right side, 9 October 2018, Beek 2018.85 ( L); Kleinmond, road to Hermanus, short before the end of the R 44 on the right side, 14 November 2019, Beek 2019.91 ( L) .

Note: —A specimen in Kew, ‘S. Africa. Drège’, ‘ R. discolor EM a’, stored as R. rigidus (K000312553) might also belong to this hybrid.

Figures

FIGURE 30. Rubus pinnatus × rigidus. A. Primocane with leaves. B. Primocane with leaves. C. Primocane. D. Leaf abaxially. E. Leaf abaxially. F. Flowering branch. G. Flowering branch. H. Inflorescence. I. Inflorescence. J. Inflorescence. K. Flower. Photographs:A. van de Beek.