sporangia

Indusium The flap of tissue, derived from the placenta, that encloses the developing sporangia in the sorus of a fern.

是一种起源于胎座（应为叶表皮译者注）的瓣片状组织，蕨类植物孢子群中正发育的孢子上。

There are a lot of sporule mother cells in every sporangium, they are respective via meiosis hind, produce the sporule of 4 monoploid.

每个孢子中有许多小孢子母细胞,自经减数分裂后,产生四个单倍体的小孢子。