Catalyst-assisted growth of boron nanowires and novel tube-catalytic particle-wire hybrid boron nanostructures were achieved by pyrolysis of diborane at 820-890 degrees C and similar to 200m Torr in a quartz tube furnace. Electron microscopy imaging and diffraction analysis reveal that most of the nanostructures are amorphous. Elemental analysis by EELS and EDX shows that the nanostructures consist of boron with a small amount of oxygen and carbon. Possible growth mechanisms for the tube-catalytic particle-wire hybrid boron nanostructures are discussed.