Domain Eukaryota
Glaucophyta

The Glaucophyta are a small kingdom of freshwater algae.

Like other Archeoplastida, they have chloroplasts surrounded by two membranes, the remains of directly absorbed symbiotic cyanobacteria.

The Glaucophyta chloroplasts, called cyanelles, retain the primitive features of the original blue-green cyanobacteria. These include the pigment phycobilin (which captures specific wavelengths of light) and a thin peptidoglycan wall between the two membranes. These are lost in the Land Plants and Green Algae (Chlorplastida).

The Glaucophyta (like many Green Algae) have two flagella of unequal length, sometimes covered with fine hairs. These are controlled by a layered microtubule structure. They have flat mitochondria and reproduce by splitting, with two identical sets of chromosomes (mitosis).

The kingdom's name comes from glauco-, "bluish-green". They are sometimes called Glaucocystophyta or Glaucocystids.There are three groups:

• The Glaucocysta are non-mobile with a cellulose cell wall (like Land Plants).
• The Cyanophora are mobile with no cell wall.
• The Gloeochaete have both mobile and non-mobile forms and a cell wall not made of cellulose.

The Glaucophyta branched off early from the super-kingdom Archeoplastida and are interexting for scientists studying the origins of the Land Plants and Green Algae.