This may be a dumb question but I'm assuming that when gemmae turn black that means they're dead. I received some D. ericksonae x pulchella gemmae along with some others in the mail and placed them in my terrarium. All were green when I set them on their media. The next day the D. ericksonae x pulchella gemmae were black. I cut one in half and viewed it under a micrscope and it was green inside just black on the outside. Perhaps I'll do better another time. I now mourn their loss.