1. Zoospore: One or more cells of Ulothrix develop into zoosporangium under favorable conditions. The protoplast of the zoosporangium divides into 32 protoplasts. Each immature protoplast transforms into a four-flagellated zoospore or cell. Zoospores are of two types. Microzoospores (8-32 per zoosporangium) and megazoospores (1-4 per zoosporangium). Zoospores are pear-shaped and have an eye spot. They emerge from the zoosporangium encased in vesicles. The vesicles then rupture and the zoospores float freely. After 2-6 days of swimming, the zoospores lose their flagella and are enveloped by walls. Later divides to form new Ulothrix filaments.
2. Aplanospore: Protoplast of sporangium divides in unfavorable environment to produce stationary molecule. It becomes aplanospore or resting spore covered by a wall. Under favorable conditions it breaks through the wall and germinates to form new Ulothrix filaments.
3. Hypnospore: Protoplast of one or more cells is covered by a hard wall due to prolonged dormancy to form spherical hypnospore. Under favorable conditions, hypnospores germinate directly into new algae.
4. Akinity: In unfavorable environment one or more cells of Ulothrix swell up with abundant food storage and develop into resting spore covered by thick wall. These cells are called akinites. Each actinomycete germinates into a new alga in a favorable environment.
5. Pameloid: In extremely dry conditions, the protoplast of the body cell of Ulothrix divides to form numerous daughter cells. Aberrant cells are covered by a gelatinous membrane. This condition is called Pamela Dasha. Under favorable conditions the gelatinous coating dissolves in water flow and each cell transforms into a zoospore. Each zoospore develops into a new alga.