Ipomoea orizabensis (G. Pelletan) Ledeb. ex Steud.

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

261. Ipomoea orizabensis (G. Pelletan) Ledeb. ex Steud. , Nomencl. Bot. 1: 818. 1840. (Steudel 1840: 818)

Convolvulus orizabensis G. Pelletan, J. Chim. Med. 10: 11. 1834. (Pelletan 1834: 11). Type. MEXICO. Veracruz (lectotype, icon. in J. Chim. Méd. 10: 11. t. 2, designated by McDonald (1994: 85).

Convolvulus serotinus DC., Cat. Pl. Horti Monsp. 97. 1813. (Candolle 1813: 97), non Ipomoea serotina Roem. & Schult. (1819) . Type. MEXICO. Sine data. (holotype MPU013593).

Ornithosperma serotina (DC.) Raf., Fl. Ludov.: 149 (1817). (Rafinesque 1817: 149).

Quamoclit serotina (DC.) G. Don, Gen. Hist. 4: 259. 1838. (Don 1838: 259).

Pharbitis serotina (DC.) Choisy in A.P. de Candolle, Prodr. 9: 341. 1845. (Choisy 1845: 341).

Ipomoea tyrianthina forma serotina (DC.) Voss, Vilmorins Blumengärtn. 711. 1894. (Voss 1894-96: 711).

Convolvulus superbus Kunth , Nov. Gen. Sp. 3: 103. 1818 [pub. 1819]. (Kunth 1819: 103). Type. MEXICO. entre Aguscarco & montañas de Jorullo, Humboldt & Bonpland s.n. (holotype P00670754).

Ipomoea superba (Kunth) G. Don , Gen. Hist. 4: 275. 1838, (Don 1838: 275), nom. illeg, non Ipomoea superba Ledeb. (1822) .

Convolvulus sanguineus Willd. ex Roem. & Schult. Syst. Veg. 3: 302. 1819, (Roemer and Schultes 1819: 302), non Ipomoea sanguinea Vahl (1794) . Type. MEXICO. Jonello & Toluca, Humboldt & Bonpland s.n. (holotype B-W03704).

Ipomoea tyrianthina Lindl. , Edwards’s Bot. Reg. 24: 87. (Misc. 162). 1838. (Lindley 1838c: 87). Type. Cultivated from seeds collected by Dickson (holotype CGE00071, isotype K).

Pharbitis tyrianthina Hook. , Bot. Mag. 69: t. 4024. 1843. (Hooker 1843: t. 4024)

Pharbitis longipedunculata Martens & Galetti , Bull. Acad. Roy. Sci. Bruxelles 12 (2): 271. 1845. (Martens and Galeotti 1845: 271). Type. MEXICO. Hidalgo, dans les bois de Sabino, H. Galeotti 1387 (holotype BR00006972677, isotypes K, P).

Ipomoea longipedunculata (Martens & Galeotti) Hemsl., Biol. Cent.-Amer., Bot. 2 (11): 389. 1882. (Hemsley 1882: 389).

Pharbitis lilacina Schltdl. ex Kunze , Linnaea 20: 31. 1847. (Kunze 1847: 31), non Ipomoea lilacina Blume (1825-26). Type. A plant sent by Ehrenberg from Mexico and cultivated at Halle (not found).

Type.

Based on Convolvulus orizabensis G. Pelletan

Description.

Twining perennial, stems pilose to glabrous, becoming muricate to spinulose when old. Leaves petiolate, 3-13 × 2.5-11 cm, ovate, entire or 3-5-lobed, cordate with rounded auricles and very narrow sinus, shortly acuminate or cuspidate, mucronate, usually pubescent or hirsute at least on the margins and abaxial veins, occasionally glabrous abaxially paler; petioles 2.5-7 cm, usually pubescent. Inflorescence of 1-5-flowered, axillary, pedunculate cymes; peduncles 2-15 cm; bracteoles 2-10 mm, filiform; pedicels 10-35 mm, commonly reflexed in fruit; sepals slightly unequal, lanceolate to ovate or elliptic, finely acuminate, shortly mucronate, glabrous, pubescent or villous, the margins white, scarious, outer (4-)11-18 × 4-5 mm, the inner usually slightly shorter, the scarious margins broader; corolla 5.5-7.5 cm long, funnel-shaped, glabrous, the tube pale, midpetaline bands ending in a mucro, the limb purple, 5-6 cm diam. Capsules ovate, 10-13 × 6-8 mm, glabrous; seeds 4-5 mm long, rounded, puberulent.

Variation.

Very variable in indumentum from glabrous to pubescent or hirsute in varying degrees. The sepals too vary from being subequal or the outer or inner slightly longer, the apex usually acuminate but sometimes obtuse. The leaves may be ovate or 3-7-lobed. Pringle 8737 has unusually finely acuminate sepals. This species was divided into four varieties by McDonald (2001) and molecular studies (Keith et al. 2017, Muñoz-Rodríguez et al. 2019) suggest I. orizabensis consists of more than one taxa. However it is unclear to date whether or not the current infraspecific classification is congruent with the molecular evidence. In any case we believe these varieties merit the status of geographical subspecies and have accordingly changed their status. The four subspecies can be distinguished by the following key: