'The Mycoplasma are organisms that completely lack a cell wall' . In contrast, Nostoc is a cyanobacterium (Eubacteria) characterised by the presence of a rigid cell wall . Aspergillus is a fungus (Ascomycetes), and fungi possess cell walls composed of chitin and polysaccharides , . Funaria is a moss (Bryophyte) belonging to Kingdom Plantae, which is characterised by cell walls mainly made of cellulose , .