Ipomoea vivianae Krapov.

Wood, John R. I., Munoz-Rodriguez, Pablo, Williams, Bethany R. M. & Scotland, Robert W., 2020, A foundation monograph of Ipomoea (Convolvulaceae) in the New World, PhytoKeys 143, pp. 1-823 : 1

60. Ipomoea vivianae Krapov. , Bonplandia (Corrientes) 18 (1): 57. 2009. (Krapovickas 2009: 57)

Type.

ARGENTINA. Salta, Dept. Rivadavia, Pluma del Pato, 13 Feb. 2005, V. Solis Neffa, J.G. Seijo, J.G. Grabiele & W. Reynoso 1985 (holotype CTES0013270, isotypes LIL, SI).

Description.

Twining perennial liana to at least 3 m, stems glabrous or sparsely pubescent when young, becoming woody with corky bark when old. Leaves petiolate, 2-4 × 2.5-5.5 cm, broadly ovate to subreniform, abruptly acuminate, shallowly cordate, glabrous or very thinly pubescent, abaxially somewhat paler; petioles 2-4 cm, slender. Inflorescence of shortly pedunculate axillary cymes, often raceme-like on short side branches; peduncles short, 1-2 cm, commonly somewhat woody; bracteoles 2 mm, caducous; secondary peduncles 5-10 mm; pedicels 10-16 mm; sepals subequal, outer 6-8 × 3-4 mm, ovate-elliptic, subacute, thinly pubescent, inner sepals c. 1 mm longer, rounded, the central part pubescent but with glabrous scarious margins; corolla 4-5 cm long, funnel-shaped, white, sometimes with pink centre, pubescent in bud and on midpetaline bands, limb 3-4 cm diam., unlobed. Capsules ovoid, 8 × 6 mm, glabrous, rostrate, the style base persistent; seeds 5 mm long, long-pilose.

Illustration.

Figure 40 .

Distribution.

A western Chaco species found in NW Argentina, western Paraguay and southern Bolivia.

ARGENTINA. Formosa: T.M. Petersen 12909 (C, CTES, G). Salta: type of Ipomoea vivianae .

PARAGUAY. Boquerón: Mayor Pedro Lagerenza, Schinini & Bordas 15091 (CTES); Col. Fernheim, Filadelfia, August & Ulmke 48 (CTES); Picada 104, Ruta Transchaco, R. Degen & F. Mereles 2979 (FCQ); Colonia 4 de Mayo, F. Mereles & R. Degen 5148 (CTES, FCQ).

BOLIVIA. Santa Cruz: Prov. Cordillera, A. Fuentes & G. Navarro 2418 (BOLV, LPB, NY, MO, USZ). Tarija: Gran Chaco, P. Zuñiga et al. 175 (HSB).

Note.

Some of the cited paratypes of this species including Krapovickas & Cristóbal 44938 (CTES), 44944 (CTES, SI), 45042 (CTES, SP) and Schinini et al. 29283 (CTES) from Amambay in eastern Paraguay are Ipomoea megapotamica . Plants from the true Chaco in western Paraguay, Argentina (Salta, Formosa) and Bolivia (Tarija, Santa Cruz) differ in the nearly glabrous leaves, usually white corolla, distinctly corky stems and, in particular, the often raceme-like inflorescence that develops on short shoots. These characters serve to separate Ipomoea vivianae from I. megapotamica but this species may eventually be shown to be only an adaptation of I. megapotamica to the arid climate of the Chaco. Krapovickas seems not to have known Ipomoea megapotamica .

Figures

Figure 40. Ipomoea vivianae. A habit B woody stem C outer sepal D inner sepal E corolla opened out to show anthers F ovary and style G fruit and calyx H seed. Drawn by Rosemary Wise A-F from Petersen 12909; G, H from Navarro 2122.