We will be rolling out several small fixes mid-day today (Jan 29.) We do not anticipate any disruptions or problems, but f you spot any unexpected issues after 12 noon (PST), please report them in the designated thread in the DG Site Updates forum.
Texas Nipple Cactus Mammillaria prolifera My best guess. Mine looks like this but is a bit larger than I've seen in pictures. I've had it for many years. Good houseplant. Seems okay without a lot of sun.