Rubus thaumasius A.Beek, 2021

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 : 40-42

17. Rubus thaumasius A.Beek nom. nov.

Replaced synonym:— Rubus immixtus Gustafsson (1934: 14) , non Foerster (1878: 155) ( Fig. 15A ).

Type:— SOUTH AFRICA. Eastern Cape: Hogsback, 4 June 1926, Rattray 4261 (holotype PRE) .

Note on name: —Because of the older homonym of Foerster (1878: 155) a replacement name for this beautiful bramble ( thaumasius = wonderful) was required.

Primocane ( Figs 15B–C ) arching, diam. 3–10 mm, roundish or obtuse angular, dark purple, densely pruinose, with some stellate hairs or almost glabrous; prickles 1–20 per 5 cm from 1–6 mm broad base, conic or sometimes triangular and bluntly compressed, patent to slightly curved, up to 2–5 mm long; stipules 9–17 mm, lanceolate-ovate, brown, tomentose and hairy. Leaves coreaceous, with conspicuous veins, usually pinnate 5-foliolate, sometimes pinnate 7-foliolate, sometimes with additional sessile leaflet at lowest yoke, rarely partially 3-foliolate, adaxially glabrous, abaxially ( Fig. 15D ) densely white tomentose; serrature rather fine, somewhat irregular, shallow, mucronate; petioles 3–7 cm, tomentose, with 7–12 curved prickles; central leaflet 41–64(–80) mm long, ovate to orbicular, with rounded or cordate base, acute or short acuminate, sometimes lobate, width–length index 0.70–0.97, length of petiolule 25–43% of length of leaflet; basal leaflets with 2–18 mm long petiolule. Flowering branch angular, furrowed, with dense stellate hairs and some sessile glands; prickles ± 7 per 5 cm, from narrow base subulate or somewhat compressed, slightly curved, up to 3 mm long. Leaves 3-foliolate or upper simple, adaxially (almost) glabrous, abaxially densely white tomentose; central leaflet broad ovate with rounded or cordate base. Inflorescence ( Figs 15E–F ) racemose, leafy only at base, cylindrical, with slightly curved prickles, short tomentose; peduncles with 1 to 2 flowers; pedicels 4–12 mm, short tomentose and with some sessile glands, with 0–3 pricklets. Flowers: sepals patent, short grey tomentose, with sessile glands; petals pink, large ( Fig. 15G ); stamens longer than styles; anthers glabrous; styles red; ovaries very densely long hairy.

Ecology: —Roadsides, hedges, ruderal terrains.

Distribution: —Centred around Hogsback, it stretches to Cathcart and Amabele, Eastern Cape, South Africa.

Specimens:— SOUTH AFRICA. Eastern Cape: Hogsback , 9 March 1988, Henderson 936 ( PRE) ; Hogsback, Rattray s.n., 1917 ( PRE) ; Hogsback , 25 November 1969, Dahlstrand 1819 ( PRE) ; Hogsback , February 1937, Giffen 111 ( PRE) ; Hogsback, road to Fort Beaufort , 20 October 2018, Beek 2018.109 ( L) ; Hogsback , 21 October 2018, Beek 2018.112, 2018.113, 2018.114, 2018.115 & 2018.118 ( L) ; Hogsback, road to Backpackers house, just south of the town to the East , 22 October 2018, Beek 2018.120 ( L) ; Amatole Mountains, near Cata , 4800 ft, 11 February 1983, Furness & Phillipson 217 ( PRE) ; Southern aspect of Windvoelberg, Cathcart , April 1962, Roberts 1810 ( PRE) ; Hopewell Farm, Katberg Range , 25 December 1911, Galpin 8352 ( PRE, 2 sheets) ; Mount Kemp , 15 January 1912, Dodd 8407 ( PRE) ; Keiskamma Hoek , 15 January 1948, Story 3285 ( PRE) ; Keiskammahoek , 14 December 1976, Gibbs Russell 3489 ( PRE) .

Note: — Rubus thaumasius is a remarkable plant with its very large flowers, strong stems and discolorous leaves. It does not look like any of the other South African brambles, but is very much similar to the Central African R. runssorensis . It is not identical to it, but it certainly belongs to the same group and it is not a hybrid of R. rigidus , as Gustafsson (1934) suggests. One could wonder if it might be introduced by British settlers who brought this remarkable plant with them from more northern regions.

Figures

FIGURE 15. Rubus thaumasius. A. Herbarium specimen. B. Habit. C. Primocane. D. Leaf abaxially. E. Inflorescence. F. Inflorescence. G. Flower. Photographs: A. van de Beek.