Ipomoea isthmica

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

175. Ipomoea isthmica J.R.I. Wood & Buril, Kew Bull. 72 (44): 2. 2017. (Wood et al. 2017b: 2)

Type.

PANAMA. Prov. Panama, Cerro Jefe, 22 Sept. 1972, A. Gentry 6135 (holotype MO).

Description.

Perennial liana to 8 m in height; stems woody, thinly pubescent, purplish-brown. Leaves petiolate, 7-15 × 6-11 cm, ovate, ovate-deltoid or suborbicular, truncate to very broadly cuneate with rounded auricles, apex very shortly acuminate and mucronulate, acute or retuse, margin entire to obscurely denticulate, adaxially green, glabrous or sparsely and softly strigose, abaxially densely silvery-sericeous, punctate, the venation prominent; petioles 3.5-8 cm, terete, pubescent. Inflorescence of compact axillary cymes with c. 3-10 flowers; primary peduncles 0.8-2 cm, grey-sericeous; bracteoles 2-3 × 0.5 mm, linear, obtuse, somewhat scarious, puberulent, caducous; secondary peduncles 3-5 mm, puberulent; pedicels 5-15 mm, puberulent below, becoming glabrous and thickened upwards; sepals unequal, glabrous, outer 5-7 × 4-6 mm, ovate to obovate, rounded, margins narrow, scarious, inner sepals 8-11 mm long and wide. suborbicular, rounded to retuse, the margins broad, scarious; corolla 4.5-5.5 cm long, funnel-shaped, glabrous on the exterior limb pale magenta, tube greenish with a purple-black base; limb c. 3.5 cm diam., apparently weakly lobed. Capsules 18-20 × 12-15 mm, ovoid, very shortly apiculate with persistent style base, glabrous, 4-seeded; seeds 5 × 2.5 mm, dark brown, broadly oblong in outline, densely lanate with matted brownish cottony hairs up to 15 mm long.

Illustration.

Figure 101A-G ; Wood et al. (2017b: 4).

Distribution.

Endemic to eastern Panama in low altitude cloud forest, 300-1000 m.

PANAMA. Chagres National Park, Cerro Jefe, A. Gentry 6135 (MO); ibid., E.L. Tyson et al. 4292 (MO); ibid., K.J. Sytsma 2018 (MO); Llano-Carti road, M. Nee 7912 (MO); ibid., G. McPherson & M. Merello 8202 (MO, PMA); ibid., T. Antonio 3731 (FTG, MO).

Note.

Readily distinguished by the large ovate-suborbicular leaves, magenta corolla with a blackish throat and unequal sepals.

Figures

Figure 101. A-G Ipomoea isthmica. A habit showing leaf and inflorescence B abaxial leaf surface C outer sepal D inner sepal E corolla opened up to show stamens F fruiting cyme G seed. H-N Ipomoea eremnobrocha. H habit showing leaves and inflorescence J abaxial leaf surface K outer sepal L inner sepal M capsule N seed. Drawn by Rosemary Wise A-E from Nee 7912; F, G from McPherson & Merello 8202; H-J