I very much doubt that the plant in RosaTimothy's photoset is r. minutifolia. The leaves, thorns, buds, bloom habit, and growth pattern bear no resemblance to any rosa minutifolia I have seen. Rosa minutifolia is an endangered species native to Baja California, and its morphology reflects its desert origins. I have worked extensively with the specimen plant of r. minutifolia grown at the UC Berkeley Botanical Garden and base my opinion from it. R. minutifolia has very small 5 cm wrinkled leaves resembling miniature gooseberry leaves. One of its synonyms/nicknames is the 'Gooseberry Rose.' The brown thorns are thin needles and thickly cover all branches, leaf ribs, and buds like stiff bristles with longer 7cm ones interspersed among the bristles. The buds are like 5 cm bristled chestnuts and come usually singly, sometimes two, or rarely three per node, but never in a cluster like RosaTimothy's pictures. The growth is arching and spreading with an established height of 36cm (14 inches) and twice as much spread, forming a thorny thicket. It spreads by underground runners as well as layering when arching branches touch the ground. The photos in the regular r. minutifolia listing are true and accurate of its morphology, and the form collected by Lewis should be identical but only with white flowers.