Zalnias were perennial flowers which grew aboard the Enterprise-D's arboretum.

In 2367, Reginald Barclay, imbued with new-found confidence given to him by the Cytherian probe, suggested to Counselor Troi that she might enjoy a walk with him in the arboretum to see the Zalnias as they were in bloom. (TNG: "The Nth Degree")