Psilotum Sporangia
The sporangia are borne on the ends of short lateral branches. Young sporangia of this plant are photosynthetic.
When the sporangia are ready to shed spores they becomes yellow.
The following two cross-sections through a “sporangium” demonstrate that there are actually three sporangia fused together (called a synangium).
The spores porduced by this plant are all the same, thus the plant is said to be homosporous. Each spore (N) will germinate to give rise to a haploid gametophyte which produces both archegonia and antheridia.
Here you can see that the sporangia have opened and all of the spores have been released.
STEMS
SPORANGIUM
STELE TYPES