Dictyota bartayresiana, commonly known as a forded sea tumbleweed,[2] is a species of brown alga found in the tropical western Indo-Pacific region and the Gulf of Mexico.

Dictyota bartayresiana grows to a height of 9 to 14 cm (3.5 to 5.5 in), being anchored to the seabed by a variably-shaped holdfast surrounded by rhizoids.

The methanolic extract is also effective as a larvicide against the mosquito Culex quinquefasciatus, and shows toxicity to the nauplii larvae of brine shrimps, a proxy for antitumour activity.

[citation needed] The diterpenes contained in this alga are distasteful to fish, which avoid eating the seaweed.

Pseudamphithoides incurvaria, a species of amphipod, feeds on the seaweed and builds a "domicile" from fragments of the fronds, and lives inside this.