A foundation monograph of Ipomoea (Convolvulaceae) in the New World Author Wood, John R. I. Author Munoz-Rodriguez, Pablo Author Williams, Bethany R. M. Author Scotland, Robert W. text PhytoKeys 2020 143 1 823 http://dx.doi.org/10.3897/phytokeys.143.32821 journal article http://dx.doi.org/10.3897/phytokeys.143.32821 1314-2003-143-1 F6F11A6EE4FF5A1885CEA2B60AE965A5 64. Ipomoea macarenensis J.R.I. Wood & Scotland , Kew Bull. 72 (10): 6. 2017. (Wood and Scotland 2017b: 6) Type. COLOMBIA. Meta, El Mico airstrip, last savannah before Rio Guajar, 6 Nov. 1949, W.R. Philipson, J.M. Idrobo & A. Fernandez 1322 (holotype BM001191225, isotypes COL, US). Description. Climbing perennial herb of unknown height; stems densely pubescent to subtomentose. Leaves petiolate, 2.5-5.5 x 2.8-5 cm, ovate, entire or shallowly 2-3-lobed, apex acute, mucronate, base truncate to shallowly cordate, adaxially green, thinly adpressed-pilose, abaxially densely silvery-tomentose with rather long appressed hairs; petioles 2-3.8 cm, pubescent. Inflorescence of few-flowered axillary cymes; peduncles 1.2-5 cm; bracteoles 12-20 x 1-7 mm, linear to oblanceolate-narrowly elliptic, foliose, variable in size and shape; secondary peduncles 6 mm; pedicels 5-6 mm; sepals subequal, densely appressed-pilose, outer 11-14 x 7-8 mm, ovate, acute, inner similar but obtuse and margins scarious, glabrous; corolla 5.5-6 cm long, white with pale pink centre, pubescent, funnel-shaped; limb c. 4 cm diam., entire; longer filaments c. 25 mm, shorter 12-14 m. Capsules and seeds not seen. Illustration. Figure 43 . Figure 43. Ipomoea macarensis A habit B adaxial leaf surface C abaxial leaf surface D outer sepal E inner sepal F corolla opened out to show stamens G fruiting inflorescence. Drawn by Rosemary Wise A-C from W. R. Philipson et al. 1322; D-G from J. Cuatrecasas 7778. Distribution. Only known from the plains below the Sierra de Macarena. COLOMBIA. Meta : J. Cuatrecasas 7778 (US, COL). Notes . This species has been identified as Ipomoea sericophylla Meisn. and it has a very similar leaf indumentum. It is, however, readily distinguished by the much larger sepals (11-14 mm long, not 6-8 mm, larger corolla c. 6 cm long, not 4.5 cm, and the much laxer, fewer-flowered cymes with foliose bracteoles. It is also similar to I. megapotamica subsp. velutina but differs in the indumentum, size and shape of the sepals. It is perhaps closest to I. opulifolia but the leaves are unlobed or only shallowly lobed and the sepals distinctly larger. The bracteoles are larger than in all these related species even when of relatively reduced size. Lindman 3189 (S) from Santa Cruz da Barra, Mato Grosso, Brazil may belong to Ipomoea macarenensis . The size of the corolla and the sepals is similar but the bracteoles are linear filiform, although persistent, and the leaves are deeply 3-lobed. It may perhaps represent yet another species or some kind of intermediate with I. opulifolia .