per·i·the·ci·um 
(pĕr′ə-thēshē-əm, -sē-əm)
(pĕr′ə-thēshē-əm, -sē-əm)n. pl. per·i·the·ci·a (-shē-ə, -sē-ə)
A small flask-shaped fruiting body in certain ascomycetous fungi that contains the ascospores.
[New Latin : PERI- + Greek thēkion, diminutive of thēkē, case; see dhē- in the Appendix of Indo-European roots.]
per′i·theci·al (-shē-əl, -sē-əl) adj.