The Collaborative International Dictionary of English v.0.48:
archesporium \archesporium\ n. 1. a primitive cell or group of cells from which a mother cell develops. Syn: archespore. [WordNet 1.5]WordNet (r) 3.0 (2006):
archesporium n 1: primitive cell or group of cells from which a mother cell develops [syn: archespore, archesporium]