Actinomycetes are without septate, mycelia tree like branched long filament structures which form radiating colony like structure. They are also referred as ray fungi. They have less than 1 um diameter. They are prokaryotic and their wall is composed of mycolic acid. Majority of them are saprotrophic (mainly actinomyces and streptomyces) which clean the environment and decompose the organic material. They also produce number of antibiotics. Fragmentation mode of reproduction is the most common. Streptomycin is the most important antibiotic produced by this species.