archesporium

noun

ar·​che·​spo·​ri·​um ˌär-ki-ˈspōr-ē-əm, -ˈspȯr- 

plural archesporia -ē-ə 

: the cell or group of cells from which spore mother cells develop

archesporial

ˌär-ki-ˈspōr-ē-əl, -ˈspȯr- 

adjective