Trentepohlia

a genus of green algae of the class Ulotricho-phyceae. There are about 60 species. The algae form a brick-red or yellow powdery coating on tree barks, rocks, and walls of buildings. The thallus, which consists of weakly branching spreading and ascending filaments, is formed from a single row of cells. The cells have a lamellate membrane, disklike chloroplasts lacking pyrenoids, and drops of oil with heterochromatic substances. The color of the thallus is determined by these substances. There are no vacuoles. The algae reproduce asexually by means of parts of the filaments, individual cells, and zoospores. Sexual reproduction (isogamy) also occurs.