Fungi - Mushrooms and Puffballs : Coccora Mushrooms
Amanita calyptroderma
Coccora Mushrooms have a symbiotic relationshop with California Live Oaks and manzanita trees, so you can often find them growing near those trees.
Pushing up a dirt cap.
Before the mushroom sprouts, it is entirely enclosed in what is called a "universal veil." As the mushroom grows, the veil membrane tears, but you can see remnants of it on both the cap and the bottom of the stipe (stem). The white on the mushroom cap is remnant of the universal veil.
The striations on the edge of the cap are one of the defining features of these mushrooms.
The extra membrane around the stem is called an annulus or ring. It is also the remnants of a veil--in this case, a partial veil. The partial veil originally covered the gills on the underside of the cap, but as the mushroom grew, this veil tore also.
You can see the remnants of the universal veil around the bottom of the stem.
The stem of Coccora Mushrooms is hollow in the center, but it can have fibrous tissue through it.