The "primary" cell of chrysophytes contains two specialized flagella.
The active, "feathered" (with mastigonemes) flagellum is oriented toward the moving direction.
The smooth passive flagellum, oriented toward the opposite direction, may be present only in rudimentary form in some species.

An important characteristic used to identify members of the class Chrysophyceae is the presence of a siliceous cyst that is formed endogenously.
Called statospore, stomatocyst or statocyst, this structure is usually globose and contains a single pore.
The surface of mature cysts may be ornamented with different structural elements and are useful to distinguish species.

Most members are unicellular flagellates, with either two visible flagella, as in Ochromonas, or sometimes one, as in Chromulina.
The Chromulinales as first defined by Pascher in 1910 included only the latter type, with the former treated as the order Ochromonadales.
However, structural studies have revealed that a short second flagellum, or at least a second basal body, is always present, so this is no longer considered a valid distinction.
Most of these have no cell covering.
Some have loricae or shells, such as Dinobryon, which is sessile and grows in branched colonies.
Most forms with silicaceous scales are now considered a separate group, the synurids, but a few belong among the Chromulinales proper, such as Paraphysomonas.

Some members are generally amoeboid, with long branching cell extensions, though they pass through flagellate stages as well.
Chrysamoeba and Rhizochrysis are typical of these.
There is also one species, Myxochrysis paradoxa, which has a complex life cycle involving a multinucleate plasmodial stage, similar to those found in slime molds.
These were originally treated as the order Chrysamoebales.
The superficially similar Rhizochromulina was once included here, but is now given its own order based on differences in the structure of the flagellate stage.

Other members are non-motile.
Cells may be naked and embedded in mucilage, such as Chrysosaccus, or coccoid and surrounded by a cell wall, as in Chrysosphaera.
A few are filamentous or even parenchymatous in organization, such as Phaeoplaca.
These were included in various older orders, most of the members of which are now included in separate groups.
Hydrurus and its allies, freshwater genera which form branched gelatinous filaments, are often placed in the separate order Hydrurales, but may belong here.
The "primary" cell of chrysophytes contains two specialized flagella. The active, "feathered" (with mastigonemes) flagellum is oriented toward the moving direction. The smooth passive flagellum, oriented toward the opposite direction, may be present only in rudimentary form in some species.
An important characteristic used to identify members of the class Chrysophyceae is the presence of a siliceous cyst that is formed endogenously. Called statospore, stomatocyst or statocyst, this structure is usually globose and contains a single pore. The surface of mature cysts may be ornamented with different structural elements and are useful to distinguish species.
Most members are unicellular flagellates, with either two visible flagella, as in Ochromonas, or sometimes one, as in Chromulina. The Chromulinales as first defined by Pascher in 1910 included only the latter type, with the former treated as the order Ochromonadales. However, structural studies have revealed that a short second flagellum, or at least a second basal body, is always present, so this is no longer considered a valid distinction. Most of these have no cell covering. Some have loricae or shells, such as Dinobryon, which is sessile and grows in branched colonies. Most forms with silicaceous scales are now considered a separate group, the synurids, but a few belong among the Chromulinales proper, such as Paraphysomonas.
Some members are generally amoeboid, with long branching cell extensions, though they pass through flagellate stages as well. Chrysamoeba and Rhizochrysis are typical of these. There is also one species, Myxochrysis paradoxa, which has a complex life cycle involving a multinucleate plasmodial stage, similar to those found in slime molds. These were originally treated as the order Chrysamoebales. The superficially similar Rhizochromulina was once included here, but is now given its own order based on differences in the structure of the flagellate stage.
Other members are non-motile. Cells may be naked and embedded in mucilage, such as Chrysosaccus, or coccoid and surrounded by a cell wall, as in Chrysosphaera. A few are filamentous or even parenchymatous in organization, such as Phaeoplaca. These were included in various older orders, most of the members of which are now included in separate groups. Hydrurus and its allies, freshwater genera which form branched gelatinous filaments, are often placed in the separate order Hydrurales, but may belong here.
Golden algae