1. IPOMŒA, Linn.
Twining or prostrate herbs, rarely suberect. Leaves alternate, entire or lobed or divided. Flowers usually large and handsome, axillary, solitary or cymose. Sepals broad or narrow, equal or unequal, erect in fruit or rarely spreading. Corolla campanulate or funnel-shaped; tube long or short; limb entire or 5-angled, more rarely slightly 5-lobed. Stamens included or exserted, often unequal; filaments filiform or dilated at the base; anthers oblong or linear, ultimately twisted or straight. Ovary 2-celled, 4-ovuled, rarely 4-celled and 4-ovuled or 3-celled and 6-ovuled; style filiform; stigma entire and capitate, or shortly 2-lobed with globular lobes. Capsule globose or ovoid, 4- or rarely 2–3-valved. Seeds as many as the ovules or fewer, glabrous or pubescent.
Taken in a wide sense, this is a genus of between 300 and 400 species, spread through all warm climates. Both the New Zealand species have a wide range in tropical countries.
| Leaves digitately divided | 1. I. palmata. |
| Leaves obtusely 2-lobed, thick and fleshy | 2. I. biloba. |
The kumara or sweet potato (Ipomœa batatas, Lamk.; Convolvulus chrysorhizus, Forst.) was introduced by the Maoris from Polynesia when they first colonised New Zealand, and constituted their chief vegetable food when the country became known to Europeans. It is still extensively grown, but has no claim to be included among the indigenous species.
1. I. palmata, Forsk. Fl. Egypt. Arab. 43.—A slender glabrous twiner; stems many feet in length, the old ones more or less tuberculate. Leaves 1–3 in. diam., digitately divided almost to the base; lobes 5–7, lanceolate or elliptic-lanceolate, obtuse or subacute, entire or the outer ones irregularly lobed, rather membranous. Peduncles erect, 1–2 in. long, 1–3-flowered. Sepals ¼–⅓ in. long, ovate, obtuse or subacute. Corolla large, 2–3 in. diam., pale-purple with a darker centre. Capsule nearly ½ in. diam., ovoid-globose, glabrous, 2-celled. Seeds 2–4, villous.—Benth. Fl. Austral. iv. 415. I. pendula, R. Br. Prodr. 486; A. Cunn. Precur. n. 396; Raoul, Choix, 44; Hook. f. Fl. Nov. Zel. i. 184. I. tuberculata, Rœm. and Schultes Syst. iv. 208; Hook. f. Handb. N.Z. Fl. 199.
Kermadec Islands: Sunday Island, not uncommon on the cliffs, T.F.C. North Island: Sea-cliffs from the North Cape to the Bay of Islands and Hokianga. December–April.
An abundant plant in the tropics of both hemispheres, attaining its southern limit in New Zealand.
2. I. biloba, Forsk. Fl. Egypt. Arab. 44.—Perfectly glabrous; stems prostrate or trailing, sometimes 40 ft. long. Leaves on petioles 1–4 in. long; blade often broader than long, 1–4 in. across, orbicular or broadly obovate or oblong, emarginate or shortly and obtusely 2-lobed, thick and fleshy, prominently veined. Peduncles
