To obtain 3-D spectral signatures of different arid rangeland plants, scientists suspend ground samples in a solvent. Electrons in molecules extracted by the solvent are excited by wavelengths of energy between 200 and 400 nanometers (nm) emitted by a xenon lamp. When the light is turned off, energy characteristic of colors in the visible light spectrum is released as fluorescence. Such information will be useful in performing fecal analysis to determine the diet of foraging animals.