Vines and Climbing Plants of Puerto Rico and the Virgin Islands

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Vines and Climbing Plants of Puerto Rico and the Virgin Islands
7. OPERCULINA
Twining vines, with milky latex. Stems, petioles, peduncles, and pedicels usually winged. Leaves
alternate, petiolate; blades simple, entire or lobed; stipules absent. Flowers bisexual, actinomorphic,
solitary or in simple dichasial cymes, axillary; peduncles longer than the petioles. Calyx campanulate,
of 5 equal or unequal sepals, usually not green, accrescent and woody in fruits, irregularly dentate at
the margins; corolla campanulate or broadly infundibuliform, the limb entire or pentagonal; stamens
5, inserted, the anthers twisted after opening; ovary superior, 2-locular, the style solitary, with two
subglobose stigmas. Fruits capsular, ovoid to globose, circumscissile, with the exocarp separating like
an operculum, the remaining layers of the fruit wall opening irregularly, or 4-valvate; seeds 4 per fruit,
glabrous or velvety. A pantropical genus of about 12 species, with the majority of the species native to
Central America and northern South America.
1. Operculina turpethum (L.) J. Silva Manso,
Enum. Subst. Braz. 16. 1836.
Key to the varieties
1a. Leaves (mature) 5-16 cm long; corollas 3-4.5
cm long……... O. turpethum var. turpethum
1b. Leaves (mature) 16-24 cm long; corollas 7-8
cm long………. O. turpethum var. ventricosa
1a. Operculina turpethum var. turpethum
Fig. 77. A-C
BASIONYM: Convolvulus turpethum L.
SYNONYMS: Convolvulus triqueter Vahl
Operculina triquetra (Vahl) H. Hallier
Slightly woody vine, twining. Stems slender,
angular, sulcate or 3-5-winged, pubescent when
young, glabrous when mature. Leaves alternate;
blades simple, 5-16 × 5-15 cm, broadly ovate,
orbicular, ovate-lanceolate, or lanceolate,
chartaceous, the apex acuminate, acute, obtuse,
or rounded and mucronate, the base cordiform or
hastate, the margins entire or slightly undulate;
upper surface glabrous or appressed-pubescent,
dull, with the venation slightly prominent; lower
surface densely appressed-pubescent, with
prominent venation; petioles cylindrical, 2.5-5 cm
long, appressed-pubescent. Flowers solitary or in
simple dichasial cymes; peduncles 2-18 cm long,
pubescent, cylindrical; bracts oblong, 2-3 cm long,
at the base of the pedicels. Calyx light green, the
sepals unequal, 1.5-2.5 cm long, the outer ones
appressed-pubescent, ovate or broadly ovate,
obtuse and mucronate at the apex; corolla white
or with the center yellowish, broadly
infundibuliform, glabrous, 3-4.5 cm long, the limb
ca. 3 cm in diameter, with obtuse lobes; stamens
and stigmas not exserted. Capsule depressedglobose,
ca. 1.5 cm long, operculate, with the
inner layers opening irregularly, covered by the
accrescent and persistent sepals; seeds black,
glabrous, subglobose, keeled, with a prominent
hilum, ca. 6 mm long.
Phenology: Collected in flower in January.
Status: Exotic, cultivated, uncommon,
probably not naturalized.
Distribution: St. Croix, St. John, and St.
Thomas. Native to the Old World.
1b. Operculina turpethum var. ventricosa
(Bertero) Staples & D. F. Austin, Brittonia 33:
595. 1981.
BASIONYM: Convolvulus ventricosus Bertero
SYNONYM: Operculina ventricosa (Bertero) Peter
Woody vine, robust, twining, attaining 10 m
or more in length, with milky latex. Stems
cylindrical, glabrous, with the pith hollow in dried
specimens. Leaves alternate; blades simple, 16-
24 × 5-15 cm, broadly ovate, chartaceous, the apex
acuminate or obtuse and mucronate, the base
cordiform, the margins entire or slightly undulate;
upper surface glabrous, dull, with the venation
slightly prominent; lower surface glabrous or
puberulous, the prominent venation appressedpubescent;
petioles cylindrical, 8-20 cm long,
appressed-pubescent. Flowers solitary or in simple
dichasial cymes; peduncles 15-20 cm long, thick,
appressed-pubescent, cylindrical; bracts ovate, ca.
3.5 cm long, deciduous. Calyx yellowish green,