The specific epithet for Coryphantha vivipara (or pincushion cactus) refers to one method the plant employs to reproduce, albeit vegetatively: vivipary, or reproducing by producing buds which grow from the main body of the plant, drop off and become new plants.
Taxonomically speaking, the Cactaceae is challenging, which I’ve noted to be typical for a plant family with a relatively recent evolutionary origin. As the writer for the Cactaceae account on the web site of the Angiosperm Phylogeny Group points out, “Depending on the author, the number of genera in the family varies by a factor of ten, the species by a factor of two…”
Photography / Photoshop resource link: Want to make your images pop off the screen or print? This tutorial on local contrast enhancement in Photoshop is a darn good solution. Almost every photograph on Botany Photo of the Day that I’ve taken has gone through this simple alteration. After running the process, I also do Edit -> Fade Unsharp Mark and adjust the slider to judge how much of the effect to apply. One warning, though–if the image already has areas that are highly saturated with colour, the effect might be over the top.