Ipomoea kahloae Gonz.

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

127. Ipomoea kahloae Gonz. - Martínez, Lozada-Pérez & Ríos-Carrasco, Phytotaxa 356 (1): 50. 2018. ( González-Martínez et al. 2018: 50)

Type.

MEXICO. Guerrero: Chilpancingo de los Bravo: a 2 km al sur del poblado de Acahuizotla, 807 m, 17°21'17.6"N, 99°27'27.4"W, 27 Aug. 2014 (fl.) C.A. González-Martínez & S. Rios-Carrasco 390 (holotype FCME; isotypes ENCB, FCME, IEB, MEXU, XAL).

Description.

Perennial climber, root woody; stems 2-5 m long herbaceous, sparsely puberulent, green, 3-winged, the wings 2-3 mm wide. Leaves petiolate, 11-17.5(-21) × 13-19(-27) cm, 5(-7) palmatilobed, the base cordate, the lobes unequal, basal lobes 5.8-13(-15) × 2-6 cm, elliptic, lateral lobes 9.2-16.7(-21.5) × 2.2-7 cm, elliptic, central lobe 9.5-19.8(-22) × 3.2-9 cm, obovate, membranous, margins entire, weakly revolute, the apex acuminate-mucronate, both surfaces puberulent, adaxially green, abaxially light green to whitish, the midvein winged, sparsely puberulent; petioles 5-13.5 cm × 1-2.2 mm, sulcate, puberulent, winged, the wings ca. 0.4 mm wide. Inflorescence of pedunculate axillary cymes with (1-)3-6 flowers; peduncles 0.8-1.1 cm, puberulent, weakly winged, not accrescent in fruit; bracteoles 1.5-2.3 × 0.9-1.3 cm, coriaceous, obovate, keeled, mucronate, exterior puberulent, pinkish-green; secondary peduncles 3.2-4.3 mm; pedicels 8 mm, thickened upwards in fruit; sepals subequal, 21-24 × 8.3-11 mm, oblong, coriaceous, puberulent, the midvein slightly elevated, base truncate, apex obtuse and mucronate, the central part pinkish-white, the margin whitish-green; corolla c. 6.5 cm long, campanulate above a narrow, cylindrical basal tube, puberulent, white, becoming magenta upwards, the interior with magenta spots and vertical lines, the basal cylindrical tube 1.5-2 long, the expanded part 3.7-4 × 3-3.5 cm, the limb 5.5-6 cm diam., subentire, weakly 10-lobed, magenta, glabrous. Capsules 1.4-1.6 × 0.9-1 cm, ellipsoid, puberulent, dark brown, the base of the style persistent, ca. 0.5 mm long, 4-seeded; seeds ca. 9.5 × 5 mm ellipsoid, the apex acute, dark brown, minutely reticulate, glabrous except for the up to 8.5 mm long marginal hairs.

Illustration.

González-Martínez et al. (2018: 51-53).

Distribution.

Endemic to Guerrero at around 800 m in semi-deciduous tropical forest.

MEXICO. Guerrero: Only known from a few collections cited by González-Martínez et al. (2018) from around the type locality.

Note.

Ipomoea kahloae is a very distinctive species with no obvious relatives. It is distinguished by the presence of strongly winged stems and petioles, the subsessile inflorescences with, pinkish-green, obovate keeled bracteoles, the pinkish sepals, and the unusually coloured a campanulate, magenta corolla. Its position here is suggested by molecular data published by González-Martínez et al. (2018).

•• Clade A2 (Species 128-215) is the second major clade within Clade A. It consists of perennial herbs and woody climbers or lianas. Most species are climbing plants but there are a few erect species. The leaves are sometimes absent at anthesis, particularly in the lianas that flower in the dry season. Although leaf shape is often a useful character, many mainly entire-leaved species sometimes present with 3-lobed leaves. The most distinctive feature of the clade lies in the rigid, subequal coriaceous sepals, which are usually glabrous (except in most species in the 128- 143 sequence). The corolla is glabrous (except Ipomoea discolor and species 129-131) and may be either hypocrateriform or funnel-shaped. The seeds, where known, are always lanate, with long marginal hairs.

The species in this clade are not always well-defined or easy to distinguish. ITS barcode sequences provide little resolution and our 605 nuclear region phylogeny included so few species that few inferences can be drawn, although there is a suggestion that the Caribbean species form a clade. It seems probable that many species have evolved recently often in response to a specific environmental stimulus. Particularly noteworthy is the existence of five species pairs which are vegetatively almost identical but differ markedly in the structure of their corolla. These are I. oranensis and I. exserta , I. schulziana and I. suburceolata , I. pintoi and I. ana-mariae , I. steudelii and I. eggersiana , I. proxima and I. macdonaldii , the first in each pair having a funnel-shaped corolla and the second a hypocrateriform corolla, the latter presumably an adaptation for bird pollination. There is also an interesting and problematic group of poorly defined Mexican species ( Ipomoea suaveolens , I. proxima , I. lottiae , I. macdonaldii , I. scopulorum , I. pseudoracemosa , I. pruinosa ), all with white flowers and forming a group in which some species seem to have switched from funnel-shaped corollas to hypocrateriform corollas, more appropriate for night-flowering moth-pollination. Other interesting features of the clade are the presence of species with stellate hairs both in South America and in the Caribbean and the existence of Caribbean species with the leaves arranged on brachyblasts ( I. eggersiana , I. steudelii , I. microdonta and I. tenuifolia ), these last all with unusually small leaves. Several species are also notable for their unusually short peduncles, the flowers thus appearing to be in axillary clusters.

The clade is well represented through most of the Americas but is particularly diverse in the Caribbean, providing all but two of the species endemic to that region. It is less common towards the north of its continental range and is almost absent from the United States.

• Species 128-131 comprise an informal group of erect Mexican species with solitary axillary flowers. They are unusual in the clade for having hirsute sepals and pubescent corollas (except I. petrophila ).