A new aerobic mesophilic genus of actinomycetes, Planotetraspora, is d
escribed. These microorganisms produce a filamentous growth which is d
ifferentiated into a vegetative mycelium and an aerial mycelium; the h
yphae are gram positive and not acid fast. Planotetraspora strains are
characterized by the formation of long, cylindrical sporangia at the
ends of short sporangiophores on aerial hyphae, with each sporangium c
ontaining four spores in a single row. The sporangiospores are release
d from the sporangia when preparations are flooded with water and are
motile by means of single polar flagella. The type species of the new
genus is Planotetraspora mira (type strain, NA9211028 [= SIIA9201]).