endosperm (en dosperm)

[ The macrospore of these plants gives rise to a small cellular prothallium bearing one or more archegonia, which in the Rhizocarps extends beyond the limits of the spore, but does not become free from it;. in the Phanerogams, where it is termed the endosperm , it remains permanently... enclosed. Encyc. Brit ., XX. 430. [ endospo