Rubus fertilis 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 : 38-40

15. Rubus fertilis A.Beek sp. nov.

Type:— SOUTH AFRICA. Western Cape:Along the R 102 between Groot Brakrivier and George, 13 January 2020, Beek 2007 (holotype L; isotype NBG). ( Figs 14A–B )

Notes: —A remarkable bramble is common around George. When inflorescences of it were seen in the herbarium it looked like a hybrid with R. affinis . However, it was in contrast to such hybrids, fully fertile (hence the chosen epithet). When spotted in the field the hybrid aspect remains. Drège distributed it as ‘ Rubus discolor E.Meyer’.

Diagnosis: —It is a shaggy plant, reminding of the European Rubus sect. Corylifolii Lindley (1835: 93) . It looks different from any other bramble in South Africa. Leaves rugose, with undulate margins, abaxially densely white tomentose; serrature rather fine, sharp, very irregular, with long thick mucros, in some parts deeply short periodical, in other parts not periodical; central leaflet broad ovate-elliptical, with rounded or emarginate base, short acuminate; prickles of the flowering branch 8–12 per 5 cm, unequal, from 3–5 mm compressed base with declined, curved or hooked slender tip, up to 4–7 mm long; inflorescence with rigid axis, pyramidal, with 3–9 axillary branches that are shorter than leaves, sometimes leafy to tip.

Primocane ( Fig. 14C ) arching, diam. 6–10 mm, angular and furrowed, with dense mainly short appressed grey stellate hairs; prickles 10–18 per 5 cm, unequal, from 2–8 mm broad base abruptly attenuate subulate or slightly compressed, patent, declining, or curved, sometimes with very short sharply hooked tip, up to 4–6 mm long, hairy; stipules 11–15 mm, lanceolate, appressed hairy. Leaves rugose, with undulate margins, bi-jugate pinnate, often with lobate or divided basal leaflets, adaxially ( Fig. 14D ) hairy especially on veins, for rest with appressed hairs, abaxially densely white tomentose; serrature ( Fig. 14E ) rather fine, sharp, very irregular, with long thick mucros, in some parts deeply short periodical, in other parts not periodical; petiole 4.5–6.0 cm long, densely short tomentose, with 12–17 curved or hooked prickles; central leaflet 41–57 mm long, broad ovate-elliptical, with rounded or emarginate base, short acuminated, width–length index 0.76–0.91, length of petiolule (12–)22–31% of length of leaflet; petiolule of basal leaflets 2–10 mm. Flowering branch ( Fig. 14F ) (obtuse-)angular, with flat or slightly furrowed sides, with dense short stellate hairs and sessile glands; prickles 8–12 per 5 cm, unequal, from 3–5 mm compressed base with declined, curved or hooked slender tip, up to 4–7 mm long. Leaves 3-foliolate with broad ovate or lobate central leaflets, sometimes also pinnate 5-foliolate or upper simple, adaxially with rather dense short appressed hairs, abaxially densely white tomentose. Inflorescence with rigid axis, pyramidal, with 3–9 axillary branches that are shorter than leaves, sometimes leafy to tip, densely short tomentose, with patent, declining and curved prickles; peduncles racemose, low to above middle divided, longest with 5–22 flowers; pedicels 0–8 mm, densely short tomentose, sometimes with some prickles. Flowers: sepals patent to erect, concave, 3–4 × 6–8 mm, short or sometimes few moderately pointed, densely grey tomentose; petals ( Fig. 11G ) pink or white, small (2–4 × 3–5 mm), roundish, long clawed; stamens shorter than styles; anthers glabrous; styles red; ovaries glabrous; receptacle with some long hairs. Ripe fruit black.

Ecology: —Roadsides, fences.

Distribution: —Common west of George (Western Cape), spreading eastward to Knysna (Western Cape) and north to Willowmore (Eastern Cape), South Africa. The precise locality of the Drège specimen is unknown.

Specimens:— SOUTH AFRICA. Western Cape: George , 18 November1935, Baker s.n. ( PRE) ; George, ‘ Agric. Expt. Station , very common along railway exclosures’, 18 November 1935, Baker s.n. ( PRE) ; Wilderness, near Fairy Knowe , 14 January 2020, Beek 2020.08 ( L) ; Knysna, February 1933, Duthie s.n. ( PRE) ; Drège s.n., ( PRE, P02579082 , ‘ R. discolor E.Mey., Afr. Austr. ’) . Eastern Cape: Buyspoort, south of Willowmore , 19 December 1950, Theron 1106 ( PRE) .

Taxonomy: —The taxonomic position of R. fertilis is not easy to define. The general aspect is much rougher than with the other Rubus ser. Scleri . The primocanes are sometimes long arching down to the ground like the Rubus ser. Rigidi , but further does not look like the beautiful species of this series. The usually high arching primocanes are like those of R. noli-tangere , just like the compound rich inflorescences. The mucronate serrature of the leaves is similar to forms of the R. mundtii -complex.

Figures

FIGURE 11. Rubus sclerus. A. Primocane. B. Pedicels. C. Herbarium specimen (Beek 2018.18). Photographs: A. van de Beek.

FIGURE 14. Rubus fertilis. A. Holotype, primocane. B. Holotype, inflorescence. C. Primocane. D. Leaf adaxially. E. Leaf serrature. F. Flowering branch. G. Petals. Photographs:A. van de Beek.