Finely reticulate is how I would have described the underside. Now smashed under a fallen tree, and dehydrated (see final photo), the upper surface is now green and striped. The first photo is much earlier, during wet weather.
Pity there's no comment about what's on the underside. I think that Trametes versicolor is a plausible ID - but other possibilities are some other Trametes or perhaps a species of Podoscypha.
I've photographed it on the underside now that it is damaged. A finely reticulate network on the surface is how I would have described it - but that probably isn't Fungi-language.
But it is understandable language! Thank you for the additional photos. In this species the upper surface has a mass of very short hairs (giving the surface a somewhat velvety feel). Algal cells and moisture are easily trapped in those hairs and it is common to see a good, green algal growth on the surface - as is the case here.