The Collaborative International Dictionary
Exannulate
Exannulate \Ex*an"nu*late\, a. [Pref. ex- + annulate.] (Bot.) Having the sporangium destitute of a ring; -- said of certain genera of ferns.
Wiktionary
exannulate
a. (context botany English) Having the sporangium destitute of a ring; said of certain genus of ferns.