I have two plants now which have Colomas as the name of the place from where the seed was collected. One is a form of M. bombycina, the other a form of M. pettersonii. M. pettersonii is reported from Guanajuato, Zacatecas, Jalisco, SLP, Aguascalientes and Durango. M. bombycina from Aguascalientes and Jalisco.
I can find a place called Coloma, in Durango, and also a Palomas, which seems to be a very common name.
So if anyone knows where this place is I'd greatly appreciate knowing. Of course I suppose there might just be two places with that name....