Random plant event: Rhipsalis NOID

I think these are maybe Rhipsalis rhombea, but I'm not sure. The tag when I bought it said it was Rhipsalis micrantha, but I decided some time ago that the tag was probably wrong.

In any case, I bought it in March 2011, and it flowered for the first time in February 2012. The flowers are self-fertile, and will produce fruit on their own, so I had seeds a short time later. I started the seeds on 15 Jun 2012. This is where they were as of mid-August:

For a sense of scale: the square of vermiculite in the photo is about 2 inches / 5 cm on a side. The vermiculite isn't normal vermiculite color, because I used un-sterilized vermiculite from a previous project, so there's . . . black stuff on it. I don't know what the black stuff is. I suppose it could be something bad, but I have more fruits, and they're fast germinators, so I can always start again.

And by the way: I know it'd probably make more sense to propagate cuttings, if I were going to propagate this plant, but 1) previous attempts to root cuttings have mostly been unsuccessful, and 2) if one of my plants produces seeds, I am unable to resist trying to germinate them.