Ipomoea durangensis House

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

130. Ipomoea durangensis House , Ann. New York Acad. Sci. 18: 187. 1908. (House 1908b: 187)

Type.

MEXICO. Durango, E.W. Nelson 4639 (holotype US0036705, isotypes GH, K).

Description.

Subshrub to 1 m, much branched at base, stems grey-tomentellous with crisped hairs, rootstock a woody xylopodium. Leaves subsessile, 2-3.5 × 0.4-1.5 cm, oblong, base cuneate, apex rounded to obtuse, grey-tomentellous on both surfaces, whitish when young; petioles 2-4 mm. Flowers solitary, axillary; peduncles 0-1 mm; bracteoles linear, filiform, 5-10 mm long, caducous; pedicels 3-10 mm, tomentellous; sepals subequal, 12-16 × 2-3 mm, but accrescent in fruit to 22 × 5.5 mm, lanceolate, acuminate, whitish tomentose; corolla 5.5-6 cm long, funnel-shaped, pale pink with the lower part of the tube cream, sericeous in bud and on mid-petaline bands, limb 4 cm diam. Capsules 12-15 × 8-10 mm, ovoid, glabrous, rostrate; seeds 4 × 4-5 mm, pubescent on margins.

Distribution.

Endemic to northern Mexico, principally Durango, in dry, open grassy habitats at altitudes of 1900-2100 m.

MEXICO. Durango: E. Palmer 366 (BM, K, MO); 6 miles W of Ciudad Durango, H.S. Gentry & R. Engard 23614 (ARIZ); 1.7 miles NE of Federico L. Madero, W.L. Wagner & J. Solomon 4319 (FTG. MO); 15-20 miles NW of Durango towards La Zarca, R.H. Hevly et al. s.n. (ARIZ); Pipasancaro, E.W. Nelson 4664 (K); Pánuco de Coronado, L. López et al. 25 (IEB); Michilia, Y. Herrera 642 (IEB); Suchil, El Mirador, P. Tenorio et al. 5967 (MEXU). Zacatecas: Oja de Agua near Sombrereta, R.H. Hevly et al. s.n (ARIZ).

Note.

Very distinctive because of the oblong, subsessile leaves and solitary axillary flowers with suppressed peduncles. The acuminate sepals should be noted.