Germicidal lamp apparatuses are provided with lamps disposed between upper and lower bases of a support structure. In some embodiments, a longitudinal axis of a lamp is at an acute angle greater than 0° relative to a region of the lower base between the lamp and another lamp. In addition, the longitudinal axis of the other lamp is at either a right angle or an obtuse angle relative to said region. Other embodiments of apparatuses include a reflector system disposed between the upper and lower bases which is common to the lamps and which includes a reflector with slanted peripheral edge. Other germicidal lamp apparatuses are provided which include a reflector with multiple sections each contoured to manipulate directionality of light emitted from a subset of lamps. In such cases, the apparatuses are configured to move the reflector and/or collectively move the lamps during illumination of the lamps.