Convolvulus austroafricanus J.R.I.Wood & R.W.Scotland, 2015

Wood, John R. I., Williams, Bethany R. M., Mitchell, Thomas C., Carine, Mark A., Harris, David J. & Scotland, Robert W., 2015, A foundation monograph of Convolvulus L. (Convolvulaceae), PhytoKeys 51, pp. 1-282 : 75-76

34. Convolvulus austroafricanus J.R.I.Wood & R.W.Scotland sp. nov. Figures 2a and 7, t. 43-51

Diagnosis.

Affine Convolvulus farinosi L. et Convolvulus aschersonii Engler sed pilis asperis, longis instructis et lobis medianis foliorum inciso-dentatis distinctis.

Convolvulus aschersonii sensu Meeuse (1958: 677).

Type.

ZIMBABWE, Salisbury [Harare], a weed, 29 June 1927, R.G. Young 18497 (holotype BM001035803!; isotype PRE).

Description.

Perennial herb, all vegetative parts pubescent with somewhat asperous, sometimes rufous hairs; rootstock a woody taproot; stems prostrate or twining, up to 2 m long. Leaves petiolate, 3-6 × 0.5-2.5 cm, variable in shape, ovate-deltoid, auriculate, sometimes the auricles lobed, the central lobe commonly oblong, apex acute, the margins undulate, sinuate-dentate to pinnatisect, base hastate; petioles 3-30 mm. Flowers 1-6 together (very rarely all solitary on the same plant) in axillary pedunculate cymes; peduncles 10-35 mm; pedicels 2-15 mm, bracts 2.5-4 mm, linear; sepals very unequal, outer sepals 6-8 × 4-5 mm, ovate to elliptic, acute; inner sepals 4-6 × 3-4 mm, nearly glabrous, apiculate; corolla 9-12 mm long, white or pale pink, lobed, the midpetaline bands pubescent, terminating in prominent teeth; ovary glabrous; style glabrous, divided c. 3 mm above base, stigmas 2.5 mm, linear. Capsule glabrous; seeds glabrous, smooth. [ Meeuse and Welman 2000: 38 (map), under Convolvulus aschersonii ]

Distribution.

South Africa (Codd 8732, Meeuse 2237, Hutchinson 2895, Codd 8732); Zimbabwe (Blenkison in Moss 14811, Peter 51118, Drummond 4904, Leach 8369); Zambia (Fanshawe 6566); Ethiopia (Mooney 5548). It is centred on Northern South Africa-Zimbabwe and is absent north of southern Zambia apart from two collections from Ethiopia.

Notes.

This species was treated as Convolvulus aschersonii by Meeuse (1958) and Meeuse and Welman (2000) but is very different from the type of that species. It is distinguished from all similar species by the spreading pubescent, slightly asperous indumentum of stem, leaves and flower parts, the pinnatisect leaves and (usually) the 4-6-flowered cymes. Towards the north of its range it tends to have fewer flowers and specimens intermediate with Convolvulus thomsonii and Convolvulus aschersonii are sometimes found. Although quite often united with Convolvulus sagittatus molecular studies ( Williams et al. 2014) support of the retention of Convolvulus austroafricanus as a distinct species.

Convolvulus austroafricanus is common in the area where Zimbabwe and South Africa meet and should be classified as Least Concen (LC) using IUCN (2012) guidelines. The epithet " austroafricanus " meaning southern Africa refers to its distribution.

A cultivated plant (Meeuse 9237A) looks very like a hybrid between Convolvulus austroafricanus and Convolvulus farinosus .