An example would be the Chaparral Dodder and Laurel Sumac. The Chaparral Dodder, a plant, grows on the Laurel Sumac (plant) to obtain nutrients.
Mutualism
An example of would be the Yucca moth and Yucca plant. The Yucca moth pollinates the plant, and in return, the moth eats the plant's seeds. Another example would be the Harvester ants and Indian Rice grass. The ants build their nest near the Indian Rice grass while protecting it from its predators. In return, the ants are able to eat from the grass.
Commensalism
An example would be the Red-Winged blackbird and Torrey pine. The Red-Winged blackbird eats the seeds of the Torrey Pine tree, and the tree is not affected in anyway.