Cyanidioschyzon merolae is a club-shaped, unicellular red algae that lives in highly acidic environments. C. merolae has a single chloroplast and a single mitochondrian, but lacks a vacuole and a cell wall. The organism's genome was the first full algal genome to be sequenced in 2004; its plastid was sequenced in 2000 and 2003, and its mitochondrian in 1998. The organism is one of the most primitive red algae.

Further reading:

Genome sequence of the ultrasmall unicellular red alga Cyanidioschyzon merolae 10D. Nature 428(6983), 653-7 (2004). [pubmed]