Ipomoea attenuata

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

37. Ipomoea attenuata J.R.I. Wood & Scotland, Phytokeys 88: 5. 2017. (Wood et al. 2017d: 5)

Type.

BRAZIL. Distrito Federal, Loc. Gama, BR 60, ca. 8.2 km do Tevo, DF-180 SO, disturbed campo sujo, dispersed locally, 15.5756S, 48.1059W, 1030 m, 26 Feb. 2015, M. Mendoza, J.B.A. Brugel, A.A. Santos, T. Reis & T.K.M. Arquelão 4802 (holotype UB, isotypes CEN, K).

Description.

Perennial herb; rootstock a woody xylopodium; stems up to 80 cm long, 2 mm diam., decumbent, weakly ascending or, fide field notes, climbing, pubescent with relatively long, often twisted spreading and appressed hairs. Leaves shortly petiolate, 4-10 × 0.3-0.7 cm, narrowly oblong, entire, apex acute and shortly mucronate, base cuneate, both surfaces thinly pubescent but more densely abaxially; petioles 3-7 mm long, pubescent. Inflorescence of lax, compounded axillary cymes from the middle and upper leaf axils; cymes up to 15 cm long, rather narrow, diminishing in size upwards, irregularly racemose in form; peduncle 2-7 cm long, often extending into a rhachis, pubescent; primary bracteoles foliose, 9-12 × 1-3 mm, linear, acuminate, persistent; secondary peduncles 0.5-2 cm long, thinly pubescent; ultimate bracteoles 4-7 × 0.5-1 mm, linear lanceolate, finely acuminate, persistent; pedicels very short, 3-5 mm long, a few scattered hairs present; calyx ovate in outline; sepals subequal, 11-14 × 4-5 mm, ovate with distinct truncate base and long-attenuated acuminate apex, glabrous, the inner very slightly longer than outer sepals; corolla 4-5 cm long, funnel-shaped, pink or reddish-purple, pubescent on the midpetaline bands, limb c. 2.5-3 cm diam. Capsules 13-15 × 8 mm, ovoid, glabrous; seeds 7 × 3.5 mm, ellipsoid, blackish-brown, glabrous except for pubescence along the angles.

Illustration.

Figure 30 .

Distribution.

Endemic to the Distrito Federal and Goiás State in Brazil, where it appears to be a rare species of cerrado.

BRAZIL. Dist. Fed.: type collection. Goiás: Samambaia, Rio Corumbá, E.P. Heringer 11283 (NY); Mun. Luziânia, Santo Antonio do Descoberto, R.C. Mendonça 93 (IBGE, NY); Serra dos Pireneus, c. 20 km S of Corumbá de Goiás, H.S. Irwin et al. 11019 (NY).

Note.

The attenuate sepal tips raise doubts about this tentative placement as this shape is atypical of species in this clade. Ipomoea attenuata has generally been treated in herbaria as Ipomoea campestris Meisn. because of the similar leaves and the pubescent exterior of the corolla, but is readily distinguished by the distinctive ovate sepals with truncate base and long attenuate apex. Additionally the inflorescence is of elongate complex cymes, somewhat racemose in form and with distinctive persistent linear-lanceolate bracteoles. The form of the inflorescence (axillary cymes) combined with the oblong leaf shape strongly suggests this is essentially a decumbent species even though this is not indicated in field notes.

Figures

Figure 30. Ipomoea attenuata. A habit B xylopodium C section of stem showing indumentum D sepals outermost (left) to innermost (right) E corolla opened out to show stamens F ovary and style G capsule H seed. Drawn by Rosemary Wise A-E from H. S. Irwin et al. 11019; F-H from M. Mendoza et al. 4802.