1) Having no petals 2) Of flowers 3) Petalless 1) Petalless 
without petals.
without petals
• (a.) Having no petals, or flower leaves. [See Illust. under Anther].
lacking petals
<botany> Without petals. ... (09 Oct 1997) ... 
lacking petals
A·pet'al·ous (ȧ*pĕt' a l*ŭs) adjective [ Prefix a- not + petal .] (Botany) Having no petals, or flower leaves. [ See Illust. under Anther ]. 
No petals; petals missing.
without petals
Apetalous is a botanical term applied to flowers or flowering-plants which are destitute of petals or corolla.
[adj] - of flowers
apetalous Without petals.
petalless adjective (of flowers) having no petals
A flower having no pedal, such as a Lindera sp.
A flower having no pedal, such as a Lindera sp.
having no petals.