Habit: Megathyrsus maximus grows as clumping perennial to 2 m in height when flowering. The nodes are pubescent. The leaves are arranged alternately to 75 cm in length (usually shorter) and to 3 cm wide, with a pubescent or glabrous basal sheath extending along the stem. At the point of divergence of the leaf sheath to the leaf blade is a membranous ligule. The leaves are parallel veined.
The zygomorphic flowers are arranged in a panicle made of spikelets. At the base of each spikelet are 2 structures called glumes. The first glume small and the second larger. In each spikelet there are flowering structures each is subtended by 2 additional structures (lemma and palea). There are two florets with the lower one sterile and reduced while the upper fertile with 3 stamens and a superior ovary each with a single locule and seed. The fruit is a caryopsis.
Habitat: Megathyrsus maximus grows in Human Altered environments (farms, old fields, waste areas).
Distribution: Megathyrsus maximus is NOT native to the Lucayan Archipelago but occurs on many islands. It is native to Africa but has been spread throughout tropical and subtropical regions of the world.
Medicinal/Cultural/Economic usage: Megathyrsus maximus is not known to be used medicinally in the Lucayan Archipelago.
It has been used a forage species.