Here is a hairy goldenaster (Heterotheca villosa) seed. The plant's leaves are aromatic with a sage-like smell. The Navajo used it to treat toothache and ant bites. It grows in abundance on hot dry south facing slopes of the Boulder County, Colorado foothills. This seed's dimensions are about 1.1 x 2.5 mm.
Equipment used: AmScope M150C microscope with Raspberry Pi camera module V2 (8MP).