t's time for the weekly nature identification thread! Post pictures of plants, animals, rocks, or other cool stuff that you've photographed but can't identify, and I, along with anyone else who would like to help, will try and help you identify it. I'll be making some changes to it- most notably, I'll be using the SBD proceeds from this post to give out 
A volcanic bomb. Volcanic bombs are blobs of magma hurled through the air by a volcanic eruption that begin to harden and solidify in midair. They come in all sorts of shapes and sizes, ranging from spheres 5 meters across to ribbons only a few inches long. (A volcanic bomb needs to be at least 2.5 inches across to qualify as such.) This particular type of volcanic bomb is known as an almond volcanic bomb, for obvious reasons. The longitudinal lines are evidence of the bomb spinning in midair as it fell and hardened. The first sample I ever collected as a geology student was a volcanic bomb. [Image source]
Remember: The most important information you can give along with any photo to be identified is its geographical location. This narrows down the range of possibilities more than any other info you can provide.
Plants:
Along with the photo, add where you found it, the time of year, the approximate altitude, and any interesting scents or textures not caught in the photo.
Animals:
Along with the photo, add the location you found it, the time of year, the sounds it made, any interesting behaviors, and any other features not caught well in the photo.
Rocks:
Along with the photo, add the location you found it, a description of the terrain it was found in, whether it was attached to a rock outcrop or found loose on the ground or buried in the soil, a description of its texture (especially its grain size), and a description of its weight and density. Fossils are included in this category.
Fungi:
I will not be identifying mushrooms and fungi for foraging. Mushrooms should really only be identified for foraging purposes in person and by an expert. If another contributor wishes to identify them, that's their call, but I encourage them to be similarly cautious. I might also try to identify a few fungi that are clearly not being looked at for the purposes of eating, but that'll be a case by case decision.
Bibliography:
