Ulothrix is a multicellular algae. Its body is made up of small unicellular cells. The cells look the same. Cells may be of greater width than length or of equal length and width. Body cell length 2-6 times greater than width depending on the species. Physiological growth of algae occurs due to the increase in the number of body cells. Hence its physical growth is indeterminate. Cells are green and produce food through photosynthesis.