Rubus leptostelechus A.Beek

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 : 18-19

6. Rubus leptostelechus A.Beek nom. & stat. nov.

Replaced synonym:— Rubus pinnatus forma glaber Gustafsson (1934: 46) .

Lectotype (designated here):— SOUTH AFRICA. Eastern Cape: ‘Prov. Cap. prope Port Elizabeth in monte Zuurberg’ , 7 September 1930, Th.C.E. Fries, Tycho Norlindh et Henning Weimarck, exped. suecica in Africam austr. et Rhodesiam austr. 1930–31…. 710 (lectotype LUND; isolectotype PRE). ( Fig. 4A )

Primocane ( Figs 4B–D ) arching, bluntly angular, diam. 7 mm, glabrous, eglandular, pruinose; prickles 6–13 per 5 cm, unequal, from 0.5–3.0 mm wide base, acicular, subulate or somewhat compressed, declining or curved, finest 1 mm, largest up to 3 mm long; stipules 6–8 mm, linear, with few hairs, green. Leaves pinnate 9- to 11-foliolate, adaxially ( Fig. 4E ) glabrous, abaxially ( Fig. 4F ) with some hairs only on main nerves, reddish when young; serrature mediocre, double, very short periodical, with straight dents with short to mediocre mucros; petiole 6–8 cm long, with 6–8 very small curved prickles, with few short stellate hairs, eglandular; central leaflet 57–64 mm long, ovate, with subcordate base, gradually attenuate into long tip, sometimes lobate or one sided divided, width–length index 0.41–0.54, length of petiolule 19–29% of length of leaflet; petiolule of lowest leaflets 4–6 mm. Flowering branch angular, furrowed, with thin appressed short stellate hairs, somewhat pruinose; prickles unequal, aciculate, or from 1–3 mm base slightly compressed, curved, 1–2 mm long. Leaves pinnate 7- to 9-foliolate, uppermost 5-foliolate; central leaflet 40–65 mm long, narrow ovate or sometimes lobate, with attenuate, rounded to subcordate base, gradually attenuate into short point without distinguishable tip, width–length index 0.48–0.70, length of petiolule 12–36% of length of leaflet. Inflorescence ( Fig. 4G ) with 2 to 3 axillary branches and pyramidal tip, short tomentose hairs, with many fine patent or declining, sometimes slightly curved prickles; pedicels ( Fig. 4H ) thin, often fasciculate, 7–18 mm, tomentose and with (almost) appressed longer stellate hairs, with very fine prickles and some subsessile glands. Flowers: sepals narrow, very long pointed, 1.5–2.5 × 6–8 mm, erect, (greenish) grey tomentose, with few subsessile glands, without prickles; petals ( Fig. 4I ) pale pink; stamens shorter than to almost equalling styles; anthers glabrous; styles red; ovaries with few hairs, often becoming glabrous; receptacle with short hairs. Fruit ( Fig. 4J ) orange, finally sometimes dark red.

Note: — Gustafsson (1934) described of R. pinnatus forma glaber . This is the most common of the glabrous R. ser. Pinnati in the eastern regions. It differs from the western R. ser. Pinnati by its glabrous primocane and from the other eastern forms by thin pedicels and weak prickles. Because the epithet ‘ glaber ’ is not available at species level, the name R. leptostelechus (‘with thin pedicels’) was chosen.

Ecology: —Forests and woody roadsides in high rainfall regions.

Distribution: —From Port Elizabeth (Eastern Cape) northward up to Tzaneen (Limpopo), South Africa.

Specimens:— SOUTH AFRICA. Limpopo : Haenertsburg, November 1913, R. Pott 13310 ( PRE). Mpumalanga : Sabie, road to Graskop, 5 km before Graskop, 1 February 2019, Beek 2019.6 (L). Eastern Cape: Hogsback, Stockenstrom, 19 December 1940, W. J. Barker 865 ( NBG); Amatole Mountains near Hogsback, along Hogsback Pass , 3650 ft, P.B. Phillipson 938 (PRE); Hogsback Pass, T.E. Repton 5726 (PRE).

Figures

FIGURE 4. Rubus leptostelechus. A. Isotype in PRE. B. Primocane with leaves. C. Primocane. D. Primocane. E. Leaves adaxially. F. Leaves abaxially. G. Inflorescence. H. Pedicels. I. Flowers. J. Fruit. Photographs: A. van de Beek.