Vines and Climbing Plants of Puerto Rico and the Virgin Islands

Vines and Climbing Plants of Puerto Rico and the Virgin Islands 49
ovary superior, bicarpellate, bilocular. Fruits capsular, globose at the base, with the apex in the form
of a beak; seeds subglobose. Approximately 200 species of the Paleotropics, 12 of which have been
cultivated and have become naturalized in the Neotropics.
Key to the species of Thunbergia
1a. Petioles winged; corolla orange or pale yellow, with the center dark violet .................... 1. T. alata
1b. Petioles not winged; corolla white or violet, with the center white or light yellow ................2
2a. Herbaceous vine, 2-3 m in length; corolla white, with the limb 4-5 cm in diameter... 2. T. fragrans
2b. Woody vine, 10-15 m in length; corolla lilac or whitish, with the limb 6-7 cm in diameter ................
.............................................................................................. 3. T. grandiflora
1. Thunbergia alata Bojer ex Sims, Bot. Mag.
52, t. 2591. 1825.
Fig. 14. G-L
Susana, Viuda, Black-eye susan, Clock vine
Herbaceous vine, creeping or climbing,
twining, 2-3 m in length. Stems cylindrical,
slender (ca. 2 mm), puberulous. Leaves opposite;
blades 4.5-10.5 × 3.2-6 cm, ovate, lobed,
chartaceous, the apex acute, the base
subcordiform; upper surface dark green, dull,
pubescent; lower surface pale green, dull, with
prominent venation; petioles 4-8 cm long, winged,
pubescent. Flowers axillary, solitary; pedicels
pubescent, 4-5 cm long; bracts green, ovate,
pubescent, 1.5 cm long, covering the calyx and
the corolla tube. Calyx yellowish green, with 12
filiform lobes, ca. 4 mm long; corolla orange, pale
yellow, or less frequently whitish,
infundibuliform, with 5 lobes, the tube ca. 2.5 cm
long, narrow at the base, dark violet inside, the
lobes ca. 2.5 cm long with the apex truncate, the
limb ca. 5 cm in diameter; stamens with glandular
hairs on the basal portion. Capsules ca. 4 mm
long, depressed-globose to 4-lobed at the base,
the upper half in the form of a beak, dehiscent by
two valves; seeds 2 or 4, 1.2-1.5 mm long,
semicircular, reticulate.
Phenology: Flowering sporadically throughout
the year.
Status: Exotic, very common, naturalized in
Puerto Rico.
Distribution: Throughout Puerto Rico,
especially in moist disturbed areas, at lower to
upper elevations. Also on St. Croix. Native to
eastern Africa, but introduced throughout the
tropics.
Public forests: Cambalache, Carite, El
Yunque, Guilarte, Maricao, Río Abajo, Toro
Negro, and Tortuguero.
2. Thunbergia fragrans Roxb., Pl. Coromandel.
1: 47. 1796.
Fig. 14. A-F
SYNONYM: Thunbergia volubilis Pers.
Susana blanca, Flor de nieve
Herbaceous vine, twining, 2-3 m in length.
Stems cylindrical, striate, slender, puberulous.
Leaves opposite; blades 6.5-11 × 1.8-6 cm, ovate
to lanceolate, chartaceous, the apex acute, the base
truncate or subcordiform; margins undulate and
ciliate; upper surface dark green, glabrous or
somewhat scabrous; lower surface pale green, dull,
puberulous, with prominent venation; petiole 2-
3.5 cm long, slender, pubescent, sulcate, with the
base somewhat dilated. Flowers axillary, solitary
or in pairs; pedicels pubescent, 5-7 cm long,
striate; bracts green, membranaceous, ovate,
pubescent, 1.6-2 cm long, covering the calyx.
Calyx green, of 15-20 sepals, lanceolate, 3-5 mm
long; corolla white, infundibuliform, with 5 lobes,
the tube 2.5-4 cm long, narrow at the base, yellow
inside, the limb 4-5 cm in diameter. Capsules 1-
2.5 cm long, depressed-globose at the base, the
upper half in the form of a beak, dehiscent in two
halves; seeds 4, globose, ca. 5 mm in diameter,
pubescent, with a depression at the base.
Phenology: Flowering and fruiting throughout
the year.