Coleochaete Brebisson
	From Greek koleos, "sheath" + chaite, "long hair"
	The thallus morphology of Coleochaete varies greatly. The genus may be prostrate and flat with radial symmetry, or may have more upright, branched filament systems. Other specimens have a combination of prostrate and upright portions. There may be a single layer of cells, or many. Species with a flat, tissue-like morphology are found more often in shallow waters than filamentous species, indicating that they have a competitive advantage in this environment.   Seta cells have extensions of the cell wall and cytoplasm. These sheathed hair cells may be as much as 100 times longer than the cell itself and help to protect the cells from herbivory. The hairs frequently break off at the edge of the sheath near the base of the hair cell, and are occasionally coiled. The seta cells differ from the other cells in that they have layered cell walls and C-shaped chloroplasts. Most cells have a single, parietal, plate-like chloroplast with at least one large pyrenoid. The thylakoids are arranged in grana, which makes them more plant-like than those of other green algae. Most or all species only grow vegetatively from the tips or edges of the thallus since they possess terminal or marginal meristems.   The variations in Coleochaete morphology may represent the evolution of the thallus morphology of land plants, as it is known that the genus is closely related to embryophytes.