The Collaborative International Dictionary
Apetalous
Apetalous \A*pet"al*ous\ ([.a]*p[e^]t"al*[u^]s), a. [Pref. a- not + petal.] (Bot.) Having no petals, or flower leaves. [See Illust. under Anther].
Wiktionary
apetalous
a. Having no petals.