is a specific kind of: herb, herbaceous plant.

is a broader term that covers: enchanter's nightshade | common evening primrose, German rampion, Oenothera biennis | Oenothera fruticosa, sundrops | Missouri primrose, Oenothera macrocarpa, Ozark sundrops.

is a member of: evening-primrose family, family Onagraceae, Onagraceae.