Sporangium

A sporangium (from Late Latin, from Ancient Greek σπορά (sporá) 'seed' and ἀγγεῖον (angeîon) 'vessel'); pl.

For Zygomycota, sexual reproduction occurs when the haploid hyphae from two individuals join to form a zygosporangium in response to unfavorable conditions.

Some lycophytes, such as the Selaginellaceae and Isoetaceae,[7]: 7  the extinct Lepidodendrales,[8] and ferns, such as the Marsileaceae and Salviniaceae are heterosporous (two kinds of spores are produced).

In ferns, sporangia are typically found on the abaxial surface (underside) of the leaf and are densely aggregated into clusters called sori.

Lycophytes, in contrast, bear their sporangia on the adaxial surface (the upper side) of leaves or laterally on stems.

Megasporangia are formed into ovules, which are borne on megasporophylls, which are aggregated into strobili on separate plants (all cycads are dioecious).

Conifers typically bear their microsporangia on microsporophylls aggregated into papery pollen strobili, and the ovules, are located on modified stem axes forming compound ovuliferous cone scales.

[citation needed] Categorized based on developmental sequence, eusporangia and leptosporangia are differentiated in the vascular plants.