A LED lamp including a cover with first and second transmissive regions that differently affect light emissions (e.g., with respect to diffusion, color, or other characteristics) transmitted therethrough. One or more apertures may be defined in a diffusive cover for a LED lamp to permit flow of air and escape of heat, and also to permit escape of directly emitted or reverse scattered light proximate to a base of the LED lamp. Multiple diffuser segments may be overlapped with intervening apertures.