Nidulariaceae is a family of fungi which is also known as bird’s nest fungi. the common name becomes quite obvious during the later stage of the fruiting body (peridium). This is when the lids open up to reveal the “eggs”, which are seed-like sacs containing spores known as peridioles. In general, four or more perioles occupy each “nest”. Some species contain forty or more.
The spore sacs are dispersed by raindrops propelling them out of the peridium. They contain a sticky substance which allows them to attach to whatever they land on.
I believe the species shown in the slideshow is Crucibulum laeve. This species grows best on dead deciduous wood. I only found bird’s nest fungus on one red elderberry branch in my back woods. When I first discovered this fungus, none of the “eggs” were exposed. However, the next week when I went to check on them, some peridioles were visible.