Mallomonas is a genus of many from the phylum Ochrophyta, which describes organisms as having heterokont flagella in some part of their life history.

In a broader context, both Chrysophyceae and Synurophyceae are referred to as “chrysophytes”, meaning “golden algae”, because of their close similarities.

[1] Pigments such as chlorophyll c1 and fucoxanthin within the chloroplasts cause the cells to have a distinct, golden or yellow-brown colour.

[1] The genus Mallomonas is based on the organization of its scales, which are silica plates that are intricately designed, species-specific, and cover the cell.

Their production is also associated with the Golgi body, the nucleus, the chloroplast, and how the complex of these organelles is arranged in relation to the SDV within the cell.

[6] Formation of the scales and bristles occurs along the chloroplast’s outer surface because of SDV’s close placement to the CER.

[1] Patterns of perforation and ridge detail vary among species, but all have a general shape consisting of a wide, rough oblong with a dome and posterior rim.

The rim can be narrow or broad, equal in length on both sides of the scale or asymmetric, depending upon the species, but the location is consistent throughout the genus and is known as the proximal end.

[1] Majority of species have a V-shaped ridge (V-rib) positioned just ahead of the posterior rim on their scales.

Also made of silica, the V-rib extends further towards the distal end and stops close to the dome (if present) or at the perimeter of the scale.

A dome is a raised portion of the base plate at the distal end where the foot of a bristle is tucked underneath.

However, this allows the bristle to rotate with the longitudinal axis of the cell through a wider angle than if it extended straight through the center of the dome.

[1] The anterior submarginal ribs and the V-rib divide the scale into regions that are in turn ornamented differently for each species.

[7] Papillae consist of small protrusions sticking out of the dome, shield, or anterior flanges that are regularly spaced, vary in density, and can be solid or hollow.

The pore-collar complex, which is the presence and shape of a silica collar around the pore (or entrance) of the stomatocyst, is taxonomically significant.

The first phase involves the primary inner wall of the cyst being formed before the collar and surface, which is thin and occurs rapidly from a proximal to distal manner.

[11] The second phase is more controlled and occurs more slowly while the wall is being thickened, and the collar and surface ornamentation are being produced.

After development has been completed, the cyst sinks down to the sediment, and remains in its resting stage until certain conditions trigger its germination.

After germination, a flagellated cell emerges from the cyst through pore-collar complex and produces new siliceous armour of scales and bristles.

In only minutes cytokinesis occurs, beginning from the anterior end and proceeding down the longitudinal axis of the cell.