Desmarestia tropica

D. tropica was first collected by William Randolph Taylor on 19 January 1935, and twice more later that month. There is a small possibility that the species still lives in deeper water in a cryptic gametophyte stage, but if so it has yet to return to the more visible sporophyte stage. The gametophyte has also never been observed. ==Description==

The thallus of D. tropica can be about tall and is soft, bushy, and light brown in color. The holdfast is tiny and not very differentiated. The stipe is in diameter and short, fleshy, and firm. It continues up as the rachis where it flattens out, only visible underneath the blade, and widens to . Opposite branching starts from the base with wide-angled branches every , and continues from each branch for several degrees. The blades have short, broad teeth which on the younger blades include short brown filaments. These filaments are oppositely branched. D. tropica differs from D. latifrons by being more bushy and having more of a gradation in branches from the apex to the base. The branches are also more expansive in D. tropica than in D. latifrons or similar species. D. tropica is in the section Herbacea of Desmarestia, but compared to other North American species it is less membranous. ==Habitat==

Tropical acidweed has been found in only two locations: Post Office Bay off Floreana Island It was once thought to be found off the mainland coast of Peru, but these specimens are considered instead to be D. firma. Despite its tropical range, it prefers the cold, deep water of upwelling areas of the lower sublittoral zone. ==References==