/kluy'steuh thee"shee euhm, -see euhm/ , n. , pl. cleistothecia /-shee euh, -see euh/ .
(in certain ascomycetous fungi) a closed, globose ascocarp from which the ascospores are released only by its rupture or decay.
Also, clistothecium .
[ CLEISTO- + THECIUM ]