The seed of Caytonia

Abstract

1. A large number of Caytonia seeds has been studied by maceration and the following new parts recognized: inner epidermis and cuticle of integument, nucellar beak forming the pollen chamber and aleurone layer. 2. Certain uncutinized parts are occasionally preserved, through some exceptional process. 3. No cutinized megaspore membrane exists in Caytonia. 4. Certain definite parts of the seed are still not understood and call for further work. 5. In having an almost completely cutinized nucellus and no megaspore cuticle Caytonia differs from nearly all Gymnosperms except a few fossils, but agrees with Angiosperms. In other respects the Caytonia seed is purely Gymnospermous.