MFC, thanks for the comments. I tried some with a white background, and some with no flash, but this one looked better to me. although the spots are too bright. Trying it outside is a good idea.
Katherine, this is striking to look at...a lot of contrast between cactus elements, and with the background. Good color and form here. (*)If this was mine, I would try photographing the subject in some different lighting situations, either using a desk lamp, or outside, and compare the results. I like what you did here. Good idea. MFC