Assemblies of tobacco mosaic virus (TMV) dried on glass substrates showed characteristic patterns which were found to be related to (1) the concentration, (2) the anisodimensional shape, and (3) the semiflexibility of the virus. The arrangements of the virus particles in the patterns were investigated using an atomic force microscope (AFM). In the dried assemblies of TMV at a concentration of 50 mg/mL, characteristic birefringent crack patterns were observed, including highly oriented regions in which the particles were uniaxially oriented but longitudinally at random, and zigzag pattern regions in which sharply bent particles having a critical bending angle of 60 degrees were found, indicating that the individual TMV particles are semiflexible rods rather than hard rods. In these regions, the interparticle end-to-end connections were frequently observed. In addition, several types of defects were observed in the crack patterns. In the dried assemblies for a TMV concentration of 0.5 mg/mL, characteristic 2D-network patterns were observed, which were formed by branching and fusing of the 2D-spindle tactoids of TMV, as well as a periodic pattern which may have resulted from spatially nonuniform speeds of the peripheral boundary of the suspension droplets during drying. The particle arrangements of the branched and fused spindles were also observed. The size of the TMV particle in the patterns was measured using the tapping mode imaging of the AFM : the length and width of the particles in the highly oriented regions were 301 and 14.7 nm, respectively, and the heights of the particles in the 2D-networks were 16.8-18.6 nm, indicating that the particles are not crushed. These values agree well with earlier ones estimated by X-ray diffraction and electron microscopy measurements. This shows that the TMV particles, in particular their highly oriented assemblies, can be used as standard specimens for the tapping mode imaging of the AFM in the scale of 10-100 nm. It was also demonstrated that single TMV particles fixed on substrates can be used to evaluate the radii of the tip apexes.