Ipomoea madrensis S. Watson

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

286. Ipomoea madrensis S. Watson , Proc. Amer. Acad. Arts 23: 281. 1888. (Watson 1888: 281)

Type.

MEXICO. Chihuahua, C.G. Pringle 1338 (holotype GH00054517, isotypes: E, F, GH, K, MEXU, MIN, MO, NDG, NY, PH, US).

Description.

Perennial herb to 50 cm from a bulb-like tuber, stems ascending or decumbent, glabrous. Leaves shortly petiolate, 1.5-5 × 0.3-4 cm, rhombic, oblong to oblong-lanceolate, acute and mucronate, cuneate at base, entire or with 2-4 small linear-oblong lobes from the base of the main lobe or ± palmately divided into 3 leaflets, glabrous; petioles 0.5-1.5 cm. Flowers solitary, rarely in pairs, axillary; peduncles 0.3-3.3 cm, usually glabrous; bracteoles 1-3 × 2 mm, filiform, moderately persistent; pedicels 4-11 mm, muricate; sepals subequal, narrowly ovate, acuminate, outer 6-10 × 4-6 mm, abaxially muricate, inner slightly larger, the midrib muricate, the margins glabrous, scarious; corolla 5-5.5 cm long, funnel-shaped, glabrous, tube white, the limb purplish, 2.5-3 cm diam. Capsules 3-locular, depressed-subglobose, 5-6 mm wide, glabrous; seeds c. 2 mm wide, densely puberulent.

Illustration.

Carranza (2007: 71).

Distribution.

Endemic to northern and central Mexico, growing in pine and oak woodland, 1600-2700 m.

MEXICO. Aguascalientes: J. Rzedowski 14159 (MEXU); Sierra del Laurel. R. McVaugh 18383 (MICH). Chihuahua: La mesa de Urucán, P. Tenorio & C. Romero 6158 (MO); Caborachi, R. Hernández 8527 (MEXU). Durango: González & Acevedo 1805 (MEXU). Est. Mexico & Dist. Fed.: Temascaltepec, Timbres, G.B. Hinton 1234 (F, GH, K, NY). Guanajuato: Sierra Santa Rosa, E. Carranza & H. Zepeda 5022 (IEB). Michoacán: Cerro El Aguila, G. Cornejo Tenorio 2810 (IEB). Nayarit: J.N. Rose 2109 (US). Querétaro: Amealco-San Juan del Río, J. Rzedowski 48571 (IEB). Sonora: Yécora, A.L. Reina-G 2000-541 (ARIZ). Zacatecas: J.N. Rose 2780 (US).

Note.

The leaves are somewhat polymorphic varying from entire to palmately lobed, a feature that together with the muricate sepals suggests a relationship with Ipomoea plummerae , which is supported by molecular results.