What I suspect to be a Mammillaria grahamii in Trents collection
Trent hails from Henderson, Nevada,U.S.A. and is both a cacti and succulent lover and prolific photographer. In fact his nickname at Davesgarden.com is "Cacti_lover". Trent raises a lot of different cacti and succulents, as witnessed by the pictures below. And some of his pictures are simply stunning! He was kind enough to contribute any pictures I wanted to use. Thanks Trent :-)
Trent especially likes Echinopsis flowers and I moved all his Echinopsis pictures to a special gallery on the Echinopsis page. You can view it HERE.