Derivation of specific name
Regularity: Regularly occurring
Global Range: Widespread species, originally from Africa, but now grows throughout Central and South America, also in Asia. 0-1000 m elevation.
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 forest: Cambalache, Carite, El Yunque, Guilarte, Maricao, Río Abajo, Toro Negro, and Tortuguero.
Solitary or paired; yellow with purple throat. Flowering throughout the year.
A depressed-globose capsule, with a long apical peak; seeds 4, globose. Fruiting throughout the year.
Leaves 5-nerved from base. Calyx bowl-shaped.
Thunbergia alata Bojer ex Sims, Bot. Mag. 52, t. 2591. 1825.
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.
Selected Specimens Examined: Acevedo-Rdgz., P. 3050; 7002; 7135; Boom, B. 9895; Eggers, B. 760; Fisher, M.J. 21; 22; 23; Goll, G.P. 71; 152; Heller, A.A. 624; 6312; 6392; Liogier, A.H. 30010; Prey, N. 82; Sargent, F.H. 189; Sintenis, P. 158; Stevenson, J.A. 98; 306; 3328; Underwood, L.M. 757.
Insects whose larvae eat this plant species
Molecular Biology and Genetics
Barcode data: Thunbergia alata
Statistics of barcoding coverage: Thunbergia alata
Public Records: 1
Specimens with Barcodes: 3
Species With Barcodes: 1
National NatureServe Conservation Status
Rounded National Status Rank: NNA - Not Applicable
Relevance to Humans and Ecosystems
Thunbergia alata, commonly called Black-eyed Susan vine, is a herbaceous perennial climbing plant species in the Acanthaceae family. It is native to Eastern Africa, and has been naturalized in other parts of the world. It is found in Cerrado vegetation of Brazil and Hawaii, along with eastern Australia and the southern USA in the states of Texas and Florida.
It is grown as an ornamental plant in gardens and in hanging baskets. The name 'Black-eyed Susan' is thought to have come from a character that figures in many traditional ballads and songs. In the Ballad of Black-eyed Susan by John Gay, Susan goes aboard a ship in-dock to ask the sailors, where her lover Sweet William has gone. Black-eyed Susan is also a name given to other species of flowers in the genus Rudbeckia.
Thunbergia alata has a vine habit, and can grow to a height of 6–8 ft (1.8-2.4 m) in tropical zones, or much less as a container plant or as an annual. It has twining stems with heart or arrow-shaped leaves. The flowers have five petals and appear throughout the growing season. They typically are warm orange with a characteristic dark spot in the centre, although different varieties can be red, orange, red-orange, white, pale yellow, or bright yellow, with or without the characteristic chocolate-purple centre which inspires the common name.
Thunbergia alata seed is easy to germinate in humus-rich soil with some sand. Soaking the seeds in a dish of warm water over night will help improve seed germination when planted. It is a fast grower, blooming quickly, with light trimming encouraging more blossoms.
- Endomelas alata ( ex Sims) Raf.
- Thunbergia alata ex Sims var. fryeri (Vilm.) Hasselbr.
- Thunbergia alata Bojer ex Sims var. albiflora Kuntze
- Thunbergia alata Bojer ex Sims var. aurantiaca Kuntze
- Thunbergia alata Bojer ex Sims var. bakeri Hasselbr.
- Thunbergia alata Bojer ex Sims var. vixalata Burkill
- Thunbergia alata Bojer ex Sims var. lutea Hasselbr.
- Thunbergia alata Bojer ex Sims var. reticulata (Hochst. ex Nees) Burkill
- Thunbergia alata Bojer ex Sims subvar. doddsii (Paxton) Hasselbr.
- Thunbergia alata Bojer ex Sims var. sulphurea Hasselbr.
- Thunbergia alata Bojer ex Sims var. albiflora Hook.
- Thunbergia alata Bojer ex Sims var. alba Paxton
- Thunbergia alata Bojer ex Sims var. retinervia Burkill
- Thunbergia albiflora (Hook.) Gordon
- Thunbergia aurantiaca Paxton
- Thunbergia backeri Vilm.
- Thunbergia doddsii Paxton
- Thunbergia fryeri Vilm.
- Thunbergia manganjensis T. Anderson ex Lindau
- Thunbergia reticulata Hochst. ex Nees
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