The New Student's Reference Work/Apetalous Flowers

Apet′alous Flowers. The phrase literally means "flowers without petals," but it is somewhat arbitrarily applied. In a complete flower there are two distinguishable floral envelopes—calyx and corolla. In case there is only one floral envelop, it is assumed that the corolla (petals) is missing, and the flower is said to be apetalous. The apetalous condition may be a primitive one, or it may have been derived by reduction from forms which had petals. Apetalous flowers are most common in what are regarded as the more primitive families of Angiosperms. The noun form of the word is apetaly.