Ipomoea littoralis Blume

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

222. Ipomoea littoralis Blume , Bijdr. Fl. Ned. Ind. 13: 713. 1825. (Blume 1825-26: 713)

Ipomoea batatas var. littoralis (Blume) Nishiyama , Bot. Mag. 84: 385. 1971 (Nishiyama 1971: 385).

Convolvulus denticulatus Lam. , Encycl. 3 (2): 540. 1789 [pub. 1792]. (Lamarck 1792: 540). Type. "Isles Mahé, Sechelles et des Trois Frères”. Commerson s.n. (holotype MPU009875, isotype P-JUSS-6810).

Ipomoea denticulata (Lam.) Choisy , Mém. Soc. Phys. Genève 6: 467 [85]. 1834. (Choisy 1834: 467 [85]), comb. illeg., non Ipomoea denticulata R. Br. (1810) .

Ipomoea nicobarica Kurz, J. Asiat. Soc. Bengal , 2 (Nat. Hist.) 45(3): 141. 1876. (Kurz 1876: 141). Type. INDIA. Nicobar Islands, Kamorta, S. Kurz s.n. (lectotype K001081746, designated here; specimen with Kurz’s annotation and type locality on label).

Ipomoea choisiana Wight ex Safford, Contr. U.S. Natl. Herb. 9: 298. 1905. (Safford 1905: 298). Type. Based on Convolvulus denticulatus Desr.

Ipomoea gracilis sensu auct. mult., non R. Brown (1810).

Type.

INDONESIA. Java, Blume 1710 (lectotype L0004194, designated here; isolectotypes L, P).

Description.

Perennial trailing or (less commonly) twining herb, stems often rooting at the nodes, glabrous or with a few hairs. Leaves petiolate, 1-7 × 2-7 cm, somewhat coriaceous, usually ovate, cordate with rounded auricles, less commonly deltoid or sagittate with acute auricles, entire but sometimes angled or lobed, apex subacute, obtuse, rounded, or retuse, mucronulate, both surfaces glabrous, veins prominent abaxially; petioles 2.5-5 cm. Inflorescence of few-flowered axillary cymes, often reduced to a single flower; peduncles sometimes paired in the leaf axils, 1-5 cm, usually much shorter than pedicels, glabrous; bracteoles 1.5 mm long, filiform, caducous; pedicels 10-25 mm, glabrous; sepals unequal, glabrous, outer 6-10 × 3-4 mm, oblong-elliptic, acute or obtuse, mucronate, inner 8-12 × 7-10 mm, elliptic to suborbicular, mucronate, the margins thin and membranous; corolla 3-5 cm long, funnel-shaped, glabrous, pale pink with a dark throat; stamens short. Capsules globose or depressed globose, 6-7 mm long, glabrous; seeds 3.5-4 mm, glabrous.

Illustration.

Figures 110C , 113 ; Bosser and Heine (2000: 47); Deroin (2001: 209).

Distribution.

Widely distributed on tropical sea shores through most of the Pacific and Indian oceans (Austin 1991c) but absent from the American and African continents, although present in Madagascar. It is especially characteristic of oceanic islands, where it is often found growing on the seashore but sometimes inland in scrub near the sea. In the Americas it is only known from the Hawaii archipelago.

HAWAII. Hillebrand 393 (K); s.n. (BM). Apparently rare fide A. Whistler (pers. com.).

Note.

The leaves of this species are very variable in shape but are characteristically succulent, the apex is usually obtuse to rounded and the base cordate with a very narrow sinus so the auricles almost touch each other. The cymes consist of only 1-3 flowers unlike the somewhat similar Ipomoea tiliacea . The mucros on the sepals are caducous like the bracteoles.

It is reported as being used as a vegetable in Polynesia (Austin 1991c).

Figures

Figure 110. Photographs of Ipomoea species. A I. grandifolia B I. lacunosa C I. littoralis D I. cryptica E, F I. batatas. A, D-F John Wood B Steven Turner C Rick Miller.

Figure 113. Ipomoea littoralis. A habit B variant leaf shape C outer sepal D inner sepal E corolla opened out to show stamens F ovary and style G fruiting inflorescence H seed. Drawn by Rosemary Wise A from Lister s. n.; B from Setchell 461; C-H from Brass 13946.