Habit: Metastelma sigmoideum grows as a glabrous, climbing vine to over 3 m in length. The leaves are oppositely arranged, to 3 cm, ovate/elliptic, with an entire margin and an acute to acuminate leaf apex. The vegetation produces a milky sap.
The complete, perfect, actinomorphic flowers are arranged in few flowered axillary cymes. The calyx has 5, unfused, sepals with triangular lobes. The corolla has 5, glabrous, petals with oblong lanceolate with acute lobes. There are 5, unfused stamens. Within the flower there are 5, white, twisted/contorted/reflexed appendages (crown) that arise from the corolla. The superior ovary has 2 locules with many ovules. The fruit is a follicle at maturity.
Habitat: Metastelma sigmoideum grows in coastal Dry Broadleaf Evergreen Formations – Forests/Shrublands (coppice) occurring on a sand substrate and Dunes.
Distribution: Metastelma sigmoideum is endemic to the Lucayan Archipelago and is known to occur in the Bimini’s and on Grand Bahama.
Medicinal/Cultural/Economic usage: Metastelma sigmoideum is not known to be used medicinally in the Bahamian Archipelago.