macrospore

The macrospores are in the shape of a low triangular pyramid with a hemispherical base, and marked with elevated ribs along the angles.

Section of a spore-case containing macrospores, equally magnified; at the right three macrospores more magnified.

It is clear, however, that in all these conidia, macrospores, microspores, and some spermatia, or by whatever names they may be called, there exists a power of germination.

The macrospore divides into two cells, a large lower one, and a smaller upper one.

The nucellus is a cellular tissue enveloping one large cell, the embryo-sac or macrospore.