Webster's Revised Unabridged Dictionary · 1913

Onagraceous

Onagraceous (on`ȧ*grā"shus) , adjective

[From New Latin Onagra an old scientific name of the evening primrose (Onothera), from Greek 'ona`gra a kind of plant; of uncertain origin.]

(Botany) Pertaining to, or resembling, a natural order of plants (Onagraceae or Onagrarieae), which includes the fuchsia, the willow-herb (Epilobium), and the evening primrose (Onothera).

Also: Onagrarieous