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Comprehensive Description

provided by Smithsonian Contributions to Botany
Ipomoea tiliacea var. merremioides Fosberg

Ipomoea tiliacea var. merremioides Fosberg, in Fosberg and Sachet, Smithsonian Contr. Bot. 21:14, 1975.

Glabrous climber but not very conspicuously twining, leaves thin, blades triangular-ovate, much longer than wide, up to 10 × 5 cm, apex tapering-acuminate, base broadly and strongly cordate with a U-shaped sinus and rounded basal lobes, petioles slender, notably shorter than blades; inflorescence umbelloid in appearance but a condensed, once to twice ramified, cymose panicle on a long peduncle, to 13 cm, pedicels much longer than branches, these 1–16 mm, bracts minute, scale-like, sepals elliptic or elliptic-oblong to slightly obovate, about 8 mm long, obtuse, outer ones mucronate, corolla funnelform, 3–3.5 cm long, limb only slightly flaring, 2.5–3 cm wide, “rose-mauve,” stamens included in basal ⅓ of throat, unequal in length, shorter than style, anthers very narrowly sagittate, straight, 2–2.5 mm long, filaments subulate, glabrous apically, increasingly beset with short gland-tipped hairs below, pollen grains globose, very shortly spinulose; pistil 16 mm long, ovary sub-globose, glabrous, style filiform, glabrous, stigma irregularly capitate, fruit globose, about 5 mm high, subtended by an entire disk, usually somewhat asymmetric, glabrous, beaked with persistent short style-base, this somewhat off-center, only one seed developed, this shot-like, 4 mm across, with 2 basal somewhat flattened areas edged on outer parts with sparse brown wool, scar light brown, obovate, surrounded by horse-shoe-shaped very low ridge, general seed-surface dull sooty brown.

The Marquesan specimens differ from those of Fiji and Tonga, as well as from the vast majority of the American ones, in being glabrous, in the much smaller much more funnelform, less flaring corollas, enlarging abruptly above the calyx, the abruptly short-mucronate rather than more gradually acuminate-aristate sepals, the usually much longer peduncles, and the entire, long-acuminate leaves rather than more or less orbicular, dentate or lobed.

SPECIMEN SEEN.—Hivaoa I.: Atikoua valley, above Atuona, 20–100 m, Sachet 1300 (US, type, P, UH); upper Puamau-Atuona trail, 500–650 m, Decker 1157 (US); Puamau-Eiaone divide, top of ridge, 300 m, Decker 932 (US); Central Pua-mau, 800–1000 ft [250–350 m], common, Decker 1071 (US, P, Fo, VC).

Operculina Manso

Operculina Manso, Enum. Subst. Braz., 16, 1836.

Coarse twining vines; leaves large, cordate; cymes axillary, pedunculate, bracteate; sepals usually accrescent; corolla broadly funnelform to campanulate; stamens included, adnate to corolla tube, anthers becoming spirally twisted; style I, included, stigmas 2, globose; ovary 2-celled, 2 ovules in a cell; fruit a capsule, the epicarp circumscissile, separating from the persistent transparent endocarp, this eventually breaking irregularly.

A small pantropical genus with two species in the Pacific, one native and widespread reaching the Marquesas.
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cc-by-nc-sa-3.0
bibliographic citation
Sachet, Marie-Hélène. 1975. "Flora of the Marquesas, 1: Ericaceae-Convolvulacae." Smithsonian Contributions to Botany. 1-38. https://doi.org/10.5479/si.0081024X.23

Comprehensive Description

provided by Smithsonian Contributions to Botany
Ipomoea tiliacea var. merremioides Fosberg

Herba scandens, foliis triangulo-ovato-cordatis valde acuminatis integerrimis, cymis valde pedunculatis umbelloideo-condensatis, sepalis mucronatis, corollis infundibuliformibus limbo distale vix expanso 3–3.5 cm longis.

Glabrous climber but not very conspicuously twining, leaves thin, blades triangular-ovate, much longer than wide, up to 10 × 5 cm, apex tapering-acuminate, base broadly and strongly cordate with a U-shaped sinus and rounded basal lobes, petioles slender, notably shorter than blades; inflorescence umbelloid in appearance but a condensed, once to twice ramified, cymose panicle on a long peduncle, to 13 cm, pedicels much longer than branches, these 1–16 mm, bracts minute, scale-like, sepals elliptic or elliptic-oblong to slightly obovate, about 8 mm long, obtuse, outer ones mucronate, corolla funnelform, 3–3.5 cm long, limb only slightly flaring, 2.5–3 cm wide, “rose-mauve,” stamens included in basal ⅓ of throat, unequal in length, shorter than style, anthers very narrowly sagittate, straight, 2–2.5 mm long, filaments subulate, glabrous apically, increasingly beset with short gland-tipped hairs below, pollen grains globose, very shortly spinulose; pistil 16 mm long, ovary subglobose, glabrous, style filiform, glabrous, stigma irregularly capitate, fruit globose, about 5 mm high, subtended by an entire disk, usually somewhat asymmetric, glabrous, beaked with persistent short style-base, this somewhat off-center, only one seed developed, this shot-like, 4 mm across, with 2 basal somewhat flattened areas edged on outer parts with sparse brown wool, scar light brown, obovate, surrounded by horse-shoe-shaped very low ridge, general seed-surface dull sooty brown.

This plant was placed with little hesitation in Merremia umbellata (L.) Hall. f., which it resembles closely in habit and appearance, especially when dried. Its straight anthers, purple flowers, and almost glabrous seeds, however, cast some doubt on this identification. On examination the pollen grains proved to be spinulose, suggesting Ipomoea. In van Ooststroom’s key (1940: 485–490) to Malaysian species of Ipomoea the plant runs readily to I. gracilis sensu van Ooststroom, non R. Brown (=I. littoralis Blume), which it is clearly not, because of the long many-flowered peduncles. It falls within the range of variation of I. tiliacea (Willdenow) Choisy, a principally American species, which occurs also (possibly as an adventive) in Fiji and Tonga. The Marquesan specimens differ from those of Fiji and Tonga, as well as from the vast majority of the American ones, in being glabrous, in the much smaller much more funnel-form, less flaring corollas, enlarging abruptly above the calyx, the abruptly short-mucronate rather than more gradually acuminate-aristate sepals, the usually much longer peduncles, and the entire, long-acuminate leaves rather than more or less orbicular, dentate or lobed.

All of the characters of this variety appear in I. tiliacea as represented in the U. S. National Herbarium, but not in this combination and not frequently. We have, at present, no opinion as to whether this and the following variety are indigenous or adventive. The distribution of I. tiliacea in the Pacific roughly parallels that of Cordia lutea Lamarck which occurs in the Marquesas and Tonga.

SPECIMENS SEEN.—Hivaoa I.: Atikoua valley, above Atuona, 20–100 m, Sachet 1300 (US, type, P, UH); upper Puamau-Atuona trail, 500–650 m, Decker 1157 (US); Puamau-Eiaone divide, top of ridge, 300 m, Decker 932 (US); Central Puamau, 800–1000 ft [250–300m] common, Decker 1071 (US, P, Fo, UC).
license
cc-by-nc-sa-3.0
bibliographic citation
Fosberg, F. Raymond and Sachet, Marie-Hélène. 1975. "Polynesian Plant Studies 1-5." Smithsonian Contributions to Botany. 1-25. https://doi.org/10.5479/si.0081024X.21