Not a specific species, but based on the local blackberries that grow like crazy in Northern California.
This is a fine art rubber stamp designed and made by Steven Vander Meer in Humboldt County, California. The die is deeply etched natural red vulcanized rubber, which is hand trimmed and adhered to red sponge cushion (the good kind, not the self-adhesive kind). The cushion is also trimmed by hand and then mounted to a smoothly sanded and oiled Maple block, with a clear black index printed on the top. The MEER IMAGE name is hot iron branded onto the end-grain of the block, and the SVM personal signature chop is added to the top of the block in red ink (space permitting).
Mount Type:Maple hardwood block indexed in black and finished with linseed oil. Block Width:1.25 inches Block Length:1.75 inches Block Thickness:3/4 inch: Image Size:Approximately 1/4 inch less than block size