'Macrosporangium' definitions:

Definition of 'macrosporangium'

(from WordNet)
noun
A plant structure that produces megaspores [syn: megasporangium, macrosporangium]

Definition of 'Macrosporangium'

From: GCIDE
  • Macrosporangium \Mac`ro*spo*ran"gi*um\, n. [NL. See Macro-, and Sporangium.] (Bot.) A sporangium or conceptacle containing only large spores; -- opposed to microsporangium. Both are found in the genera Selaginella, Isoctes, and Marsilia, plants remotely allied to ferns. [1913 Webster]