Mexico Trip Part 1 - Mammillaria haudeana

This is a picture of Mammillaria haudeana. I first found this Mammillaria just outside the town of Yecora, Sonora and again about 20 km further, towards the town of Meycoba. This picture is of the second site. I find that there are subtle difference between the two sites.

Which differences do you mean, Amante?

I do not know if I can explain myself clearly. I just know that they look different but I cannot tell which difference it is. I hadn't had the time to place two pictures together and tried to check what I feel is different but when I saw them from both location somehow I thought they looked different.

Even when I showed the slides during a lecture I gave to the Mamm. Society of Malta, some agreed that they looked different. Yet reason dictates that they should be the same given the short distance between the two localities. Perhaps it could be that one location had more precipitation than the other or some other factor. Here is a picture from the other location.