Plant
Nectarine tree (
2 US plant patents name this plant. 2 have expired, so those cultivars are free to propagate and sell.
Already in the public domain — 2 cultivars
Most recently freed first. Anyone may propagate and sell these plants — though the name it is sold under may still be a live trademark.
Botanically this is Prunus. A patent expiring frees the plant, and its cultivar name with it — cultivar names cannot be trademarked. Any brand name it is sold under is a separate thing and may still be owned.