Convolvulus aschersonii Engl., Abh. Koenigl . Akad. Wiss. Berlin 2: 349. 1892. (Engler 1892: 349).

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 : 76-78

35. Convolvulus aschersonii Engl., Abh. Koenigl. Akad. Wiss. Berlin 2: 349. 1892. (Engler 1892: 349). Figure 7, t. 23-28

Convolvulus hastatus var. multiflorus Choisy, Prodr. [A.P. de Candolle] 9: 407. 1845. ( Choisy 1845: 407). Type. SOUTH AFRICA, Northern Cape, Drège 7829 (lectotype L, designated here; isolectotype P!).

Convolvulus ulosepalus Hallier f., Bot. Jahrb. Syst. 18: 103. 1893 [ “1894”]. ( Hallier 1893: 103). Type. SOUTH AFRICA, Northern Cape, Drège 7829 (lectotype L, designated by Meeuse and Welman 2000: 46); isolectotype P!).

Convolvulus rhynchophyllus Baker & Engl. ex Hallier f., Bull. Herb. Boissier 6: 534. 1898. ( Hallier 1898a: 534). Type. Bolus 252 (K, lectotype, designated here).

Convolvulus sagittatus subvar. linearifolius Hallier f., Bull. Herb. Boissier 6: 534. 1898, as " Convolvulus sagittatus var. grandiflorus subvar. linearifolius ". ( Hallier 1898a: 534). Type. SOUTH AFRICA, Mpumalanga, Barberton, Galpin 1037 (isotypes K!).

Convolvulus sagittatus var. linearifolius (Hallier f.) Baker & C.H.Wright, Fl. Cap. (Harvey et al.) 4(2): 72. 1904. ( Baker and Wright 1904: 72). Type. Based on Convolvulus sagittatus subvar. linearifolius Hallier f.

Convolvulus sagittatus var. ulosepalus (Hallier f.) Verdcourt, Kew Bull. 12:346. 1957. ( Verdcourt 1957: 346). Type. Based on Convolvulus ulosepalus Hallier f.

Type.

ETHIOPIA, Schimper 660 (holotype B†; isotypes BM001011617!, E005-7479!).

Description.

Perennial herb, all vegetative parts similarly obscurely puberulent to pubescent; rootstock a woody taproot; stems prostrate or twining, up to 2 m long. Leaves petiolate, (0.5-) 2-10 × 0.2-4 cm, variable in shape, narrowly deltoid in outline, auriculate with the basal auricles simple or, more commonly bifurcate, the central lobe oblong to oblong-lanceolate, much longer than the auricles, apex acute to apiculate, margin entire to undulate, base commonly more or less truncate and briefly cuneate onto the petiole, leaves near base of stem often with a broader central lobe than those near apex; petioles 5-25 mm. Flowers (1-) 2-6 together (very rarely solitary) in compact axillary, pedunculate cymes; peduncles 8-35 mm; bracteoles 2-5 mm, linear or linear-lanceolate; pedicels 1-10 mm, outer sepals 5-6 (-7) × 2-3 mm, lanceolate to ovate, acute, usually pubescent, inner sepals up to 5 mm wide, suborbicular, apiculate, margins scarious, glabrous or pubescent on the midrib only; corolla 7-12 mm long, white or pink, lobed, the midpetaline bands pubescent, terminating in prominent teeth; ovary glabrous; style glabrous, divided 3-4 mm above the base; stigmas c. 3 mm. Capsule glabrous; seeds glabrous, smooth. [ Collenette 1999: 232 (as Convolvulus sagittatus ); Meeuse 1957: 678 as Convolvulus ulosepalus ; Meuse and Welman 2000: 436. p. p.; Verdcourt 1963: 44 p. p.; Sebsebe 2006 185 as Convolvulus sagittatus var. aschersonii ]

Distribution.

South Africa (Baur 901, Bolus 252, Tyson 124, Moss 14129); Namibia (Merxmuller 813, Wanntorp 815); Lesotho (Dinter 144, Dieterlen 97); Botswana (de Winter 7403, Brown 7952); Mozambique ( Macuácua 1333); Madagascar (White s.n. [16/9/1929]), Baron 5213); Angola (Welwitsch 6204); Zimbabwe (Rand 510, Chubb 375); Zambia (Fanshawe 5519, Sanane 307); Malawi (Patel & Kwatha 2708); Democratic Republic of the Congo (Symoens 13595); Ruanda (Troupin 4802); Tanzania (Grimshaw 93463, Richards 26827); Kenya (Mearns 1157, Lugard 168); Uganda (Scott Elliot 1145); Somalia (Thulin 10918); Ethiopia (Schimper 1130, Hildebrandt 498, Scott 305, Bidgood et al. 4970, Cufodontis 47); Eritrea (Schweinfurth & Riva 1061, Schweinfurth 1739, Ryding 1116); Yemen (Spellenberg 5426); Saudi Arabia (Collenette 5367); Nigeria (Lely 362).

Notes.

The type of Convolvulus aschersonii (Schimper 660) has leaves with a relatively broad central lobe 5-10 mm wide and this is matched in South African material (Dieterlen 97a has even wider leaves) but narrower lobes are much more common in southern Africa. Plants towards the northern end of the range have few-flowered cymes, quite frequently reduced to single flowers. They are often more strongly pubescent and with less pronounced, often simple basal auricles whereas bifurcate auricles are the norm further south. Examples of this northern form include Simwanda 108 from Zimbabwe, Robinson 8 from Zambia, Symoens 13595 from Congo, Eggeling 2593 from Uganda, Bally 5592 from Kenya, Newbould 774 from Somalia, Scott Jones 32 from Eritrea, Wood 3281 from Yemen and Collenette 5367 from Saudi Arabia,

Convolvulus aschersonii is most readily distinguished from Convolvulus austroafricanus by the leaf shape and the short pubescence. The central leaf lobe is entire and often very narrow, most notably in specimens from Namibia. Possible hybrids or intermediates with Convolvulus austroafricanus with strongly sinuate leaf lobes occur quite frequently in Transvaal but are hardly known elsewhere. (Hanekom 2528, Meeuse 9020, Frieberberg 3195, Wilms 983, Mogg 12299, Acocks 2169, Marais 36). From Convolvulus sagittatus and Convolvulus thomsonii it is distinguished by the usually 2-5-flowered peduncles, bifurcate auricles and corolla less than twice as long as the calyx, rarely exceeding 12 mm in length. Intermediates or possibly hybrids with Convolvulus sagittatus also occur in South Africa, (Baur 350, Galpin 1037, Wilms 2158, Meeuse 10253, Pillans 5605), Zimbabwe (Eyles 8473) and Zambia (Best 107). These have larger flowers than typical of Convolvulus aschersonii but the peduncles are 2-flowered and the leaves like those of Convolvulus aschersonii . These were, at least mostly, treated as " Convolvulus sagittatus subsp. grandiflorus var. linearifolius " by Meeuse (1958: 683).