Ulva paschima

Ulva paschima is a green seaweed from the family Ulvaceae, found only along India’s West Coast. It was recognized as a distinct species in 2014 through molecular analysis of ITS sequences, which placed it in the “Paschima” clade.

The fronds are erect, filamentous, and grass-green, ranging from 5 to 40 cm in length. They are mostly unbranched and tubular, though some parts may be flattened like ribbons.

The tufts attach to surfaces using rhizoids. Thalli growing in low-salinity water tend to be branched, while those in open ocean conditions are unbranched. The cells are roughly quadrilateral, sometimes arranged in lines, and each cell contains a parietal chloroplast with more than two pyrenoids.

This alga lives on intertidal rocks in both saline and estuarine environments, tolerating salinities from 35 down to 24 PSU.

Its life cycle involves sporangial and gametangial thalli that look identical. The diploid adult releases haploid zoospores through meiosis; these settle and grow into separate male and female haploid plants, which resemble the diploid form. When these haploid plants release gametes, they fuse to form a zygote that germinates into a new diploid plant.