Figure 21.2: Early Branching Groups of Plantae (A) The large chloroplasts of unicellular glaucophytes differ from chloroplasts of other Plantae in retaining a layer of peptidoglycan. This feature is thought to have been retained from the endosymbiotic cyanobacteria that gave rise to the chloroplasts of Plantae. This photograph shows a colony of two individuals, each with two chloroplasts. (B) The photo-synthetic pigment phycoerythrin gives this red alga its rich hue, showing up vividly against a background of sand.