Rubus trichogynus 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 : 44-45

20. Rubus trichogynus A.Beek sp. nov.

Type:— SOUTH AFRICA. Western Cape: Stellenbosch, Helshoogte , Hillcrest , parking, 24 February 2018, Beek 2018.16 (holotype L; isotype NBG) . ( Figs 17A–B )

Diagnosis: —Low weak plant with abaxially green leaves; central leaflet ovate, gradually attenuate; inflorescence axillar with 2-5 flowers; petals white, very large.

Primocane ( Figs 17C–D ) low arching to prostrate, roundish to angular, diam. 3–4 mm, with scattered long patent hairs to almost glabrous, and often some (sub-)sessile glands, in sun somewhat pruinose; prickles 10–40 per 5 cm, unequal subulate or almost acicular, up to 4–5 mm long, often brown-purple; stipules ovate-lanceolate, sometimes leafy, 12–30 mm long, green, hairy. Leaves 3-foliolate, pinnate 5-foliolate or sometimes for part digitate 5-foliolate or (sometimes incomplete) pinnate-digitate 7-foliolate, adaxially with appressed hairs, becoming almost glabrous, abaxially ( Fig. 17E ) green, soft pubescent; serrature deep, periodical, with (almost) straight teeth; petiole 5–9 cm, with some patent hairs and 10–30 unequal up to 3–5 mm long subulate or acicular declining prickles; central leaflet of 3-foliolate leaves 95–112 mm long, triangular, deep cordate, gradually attenuate, acute, sometimes lobate, width– length index 0.70–0.80, length of petiolule 23–28% of length of leaflet; central leaflet of pinnate leaves 80–110 mm long, with attenuate to subcordate base, ovate, gradually attenuate, acute, width–length index 0.66–0.76, length of petiolule 4–12% of length of leaflet; central leaflet of digitate 5-foliolate leaves 95–100 mm long with rounded base, ovate, gradually attenuate, acute, width–length index 0.60–0.66, length of petiolule 37–39% of length of leaflet; lateral leaflets sessile. Flowering branch ( Fig. 17F ) angular, with patent hairs, 5–10 acicular up to 2–3 mm long pricklets and some subsessile glands. Inflorescence ( Fig. 17G ) axillar, with 2–5 flowers; pedicels ( Fig. 17H ) ascendant, 1.5–10.0 cm long, with patent long hairs and some subsessile glands. Flowers: sepals green or slightly greyish green, densely long hairy, with subsessile glands, and 1–5 prickles, after flowering erect; petals ( Fig. 17I ) white, large ovate, elliptical or obovate, 18–23 mm long, 13–16 mm wide, width–length index 0.65–0.72; stamens shorter to somewhat longer than styles; anthers glabrous; ovaries and receptacle densely hairy. Mature fruit black.

Ecology: —Woods, fynbos.

Distribution in South Africa: —On scattered localities from Limpopo to the Western Cape.

Specimens:— SOUTH AFRICA. Limpopo: Pietersburg, Turfloop , 23 November 1972, Grobbelaar E. B.97. M ( PRE) . Mpumalanga: Graskop , 28 October 1981, Stirton 9803 ( PRE0629473 -0) ; At 7 km below Kowyn’s Pass, Graskop-Bushbuckridge road, 24 February 2001, Burrows 7318 ( BNRH0010129-1 ) ; Graskop, road to Hazyview , 20 October 2019, Beek 2019.84 ( L) . Free State: Golden Gate, Wilgehof , old cemetery, near the dam, 26 November 1990, Van Wyk & Van Wyk 2617 ( PRE) . Western Cape: Stellenbosch, Helshoogte, Hillcrest , parking, 24 February 2018, Beek 2018.16 ( L) ; Stellenbosch, Hillcrest , parking, 14 October 2018, Beek 2018.89 & 2018.91 ( L) ; Stellenbosch, Hillcrest , parking, 30 October 2018, Beek 2018.124 ( L) ; Stellenbosch, beginning of Jonkershoek Road , 24 February 2019, Beek 2019.38 ( L) ; Kogelberg State Forest, 6 October 1992, Kruger 825 ( BNRH0010129-1 ) ; Oudtshoorn, Hoogekraal, on the road from Bergplaas to Karatara , 21 October 1991, Henderson 1098 ( PRE) ; Cape Province, 19 November 1963, Louw 9 ( BNRH) . Eastern Cape: Hogsback, Laragh on Hogsback , 21 October 2018, Beek 2018.111 ( L) .

Notes: —Besides R. titanus , there are some other cultivated American blackberries that have become naturalized in South Africa and behave like normal species. Because most blackberries, also the non-cultivated taxa, have a hybridogenous origin, there is no reason why they should not be described as a species if they grow outside of confinement or cultivation like other wild taxa. One of these taxa has a wide distribution and often grows in full natural circumstances. Most South African researchers called it R. flagellaris Willdenow (1809: 549) . Sochor (2019) is more careful and attributes it only to Rubus sect. Flagellares ( Bailey 1923: 152) Bailey (1943: 231) [= R. sect. Procumbentes ( Rydberg 1913: 430) Bailey (1932: 314)] without identifying a species. It is cultivated in South Africa as the Boysenberry, but because several cultivars are bred under that name, a direct identification of the naturalized South African plants with it cannot be made. We restrict ourselves to just describing these plants from their own characteristics as a new species, that we call Rubus trichogynus , because of the pilose ovaries.

The plants do certainly not belong to R. flagellaris , with its characteristic shouldered central leaflets, but it does not even belong to that series because of its stamens of various lengths and slightly pruinose stems. The correct name of the section, which was called Rubus sect. Flagellares , is R. sect. Procumbentes and not ‘ Flagellares L.H.Bailey’, which is a later superfluous synonym ( Reveal 2014). Rubus procumbens Muhlenberg (1813: 50) is a superfluous homonym of R. trivialis Michaux (1803: 296) , which Muhlenberg (1813) cites, but this is not the type of R. sect. Procumbentes, because Rydberg (1913) excludes R. trivialis from his (unranked) Procumbentes Rydberg (1913: 430) and from his R. procumbens Rydberg (1901: 498) ; consequently R. sect. Procumbentes are typified by R. procumbens Rydberg , non Muhlenberg (ICN Art. 48.1, Turland et al. 2018).

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.