Does Cactus Change Color

Yes, cactus plants can be brown. For example, the living rock or fossil cactus [Ariocarpus spp] is gray brown in color. It isn't the only cactus that isn't green. In the way of another example, the yellow peanut cactus [Echinopsis chamaecereus f. lutea] lacks greenness of color, because it lacks chlorophyll. It has to be grafted onto a green cactus to be able to supply itself with energizing photosynthetic products.