Rubus revealii A. Beek & M.P. Widrlechner, 2021

Van de Beek, Abraham & Widrlechner, Mark P., 2021, North American species of Rubus L. (Rosaceae) described from European botanical gardens (1789 - 1823), Adansonia (3) 43 (8), pp. 1789-1823 : 79-82

Rubus revealii A. Beek & M.P. Widrlechner , sp. nov.

( Fig. 7A, B )

Primocane erect or high arching, 5-8 mm in diameter, furrowed, with scattered, fine trichomes mostly on ridges. Prickles 3-5 mm broad at base, almost straight, 4-8 mm long. Stipules 7-18 mm, linear to lanceolate, thinly hairy. Petioles 5-8 cm, appressed-pilose, with 5-10 curved or hooked prickles. Leaves palmately 5-foliolate; surfaces adaxially thinly pubescent, mostly along veins, abaxially densely pubescent, sometimes slightly greyish pilose; margins serrate, teeth rather sharp, moderate, almost straight. Central leaflets elliptic, 7-10.5 cm long, base subcordate, truncate, or rounded, apex rather abruptly attenuate; width-length index 0.53-0.68, subtending petiolules 26-33(40)% of the length of the central leaflet. Petiolules of the lowermost leaflets 0-3 mm. Flowering branches hairy. Inflorescences small (on the type, 8.5-13 cm long), cymose or short racemose. Pedicels 10-40 mm, densely hairy, pricklets 0-8, minute. Sepals ovate, 3-4.5 × 5-8(9) mm, patent to reflexed, hairy, (greyish) green with a white margin, unarmed. Petals typically 12-14 mm long, elliptic-obovate. Stamens patent, as long as or slightly longer than green styles. Anthers, ovaries, and receptacle glabrous.

HOLOTYPE. — CM, Flora of Pennsylvania, Lycoming Co.: North of Salladasburg by Pa. 84, 24.VIII.1956, H.A. Davis, T. Davis, & W. Davis 11574 (holo-, CM [ CM129946 , CM129947 ]) ( Fig. 7A, B ).

REPRESENTATIVE COLLECTIONS. — South AFrica. Freestate, Clarens , along the R 711, 2.II.2018, A. van de Beek 2018.01, L; Kwazulu Natal , road from Vryheid to Louwsburg , 3.2 km before the exit to Louwsburg , southside of the road, 14.II.2018, A. van de Beek 2018.08, L.

Swaziland. Along the MR1 south of Piggs Peak, just south of Hawane Christian Life Community Church, 12.II.2018, A. van de Beek 2018.06, L .

United States. Illinois, Vermillion County: Middle Fork State Fish & Wildlife Area , 16. VI.1991, M. P . Widrlechner 308, ISC . — Pennsylvania, Bucks County: Bowman’s Hill, rich wooded slopes along Pidcock Creek , 19.VII.1936, J. W . and M. T. Adams 2873, BH ; Huntingdon County: 2 miles NE of Franklinville , 14.VIII.1955, H. A., T ., and W. H. Davis 11089, CM ; West Virginia, Monongalia County: Morgantown , in pasture by Evansdale, 11.VII.1947, H. A . and T. Davis 8192 and 8193, BH .

DISTRIBUTION. — United States. This species “seems to be confined to the eastern states. Bailey gives the range as from New England to Virginia. It is a common, but not a very productive blackberry in old fields and fencerows in the hills of Pennsylvania and West Virginia.’’ (as stated in Davis et al. 1969b: 261).

Southern AFrica. Rubus revealii sp. nov. is an invasive species in parts of South Africa, especially in the north of Kwazulu-Natal, the east of the Free State, and the southeast of Mpumelanga, and also in Swaziland. In Kwazulu-Natal, it is accompanied by two other invaders from North America, R. probabilis L.H. Bailey and R. originalis L.H. Bailey. In South African publications ( Stirton 1984; Henderson 2001, 2011), these three taxa have usually been considered as forms of R. cuneifolius Pursh. More recently, Sochor (2018) correctly conceived the samples of R. revealii sp. nov. and R. originalis as belonging to the Arguti.

PICTURES. — Henderson (2011): 1a and c; 2: the upper series; 3: the upper series.

DISTINGUISHING TRAITS. — Rubus revealii sp. nov. has some resemblance to R. laudatus A. Berger. However , the latter has more gradually attenuated and broader leaflets, the central leaflets typically with acute tips, and stronger, leafier racemose inflorescences, except at the extreme western edge of its native range, where it can produce heavily armed, short-flaring inflorescences ( Widrlechner 2013).

Figures

FIG. 7A. — Rubus revealii A. Beek & M.P. Widrlechner, sp. nov. holotype, primocane, H.A. Davis, T. Davis, & W. Davis 11574 (CM[CM129946]).