Glaucophyta

Glaucophyta (glaucophytes, glaucocystophytes, or glaucocystids) are a small group of freshwater algae. Glaucophyta, along with Rhodophyta (red algae), green algae (divisions Charophyta and Chlorophyta) and the land plants (Viridiplantae) form the Archaeplastida. However, relationships between these groups are unclear, due to the limited study of glaucophytes.

The Glaucophyta are of interest to biologists studying the development of chloroplasts, because some studies suggest that they may be similar to the original algae type that brought rise to the green plants and red algae.

Characteristics
The chloroplasts of glaucophytes are known as cyanelles. Unlike the plastids in other organisms, glaucophytes have a peptidoglycan layer that suggests the endosymbiotic origins of plastids from cyanobacteria. Glaucophytes contain the photosynthetic pigment, chlorophyll a. Like the red algae and Cyanobacteria, the glaucophytes harvest light via phycobilisomes, structures made mostly of phycobiliproteins. The green algae and land plants have lost that pigment.

Glaucophytes have mitochondria with flat cristae, and undergo mitosis without centrioles. Motile forms may have unequal flagella, which may have fine hairs and are anchored by a system of microtubules, both of which are similar to forms in green algae.