Inonotus dryadeus (aka. Polyporus dryadeus).
Commons Names: Oak bracket, warted oak polypore, weeping polypore or weeping conk
This is a very common fungus found on oaks trees, but other hardwoods can also be hosts. It annually fruits from summer to fall and is found at ground level attached to the base of the trunk and/or larger roots of living trees. It may also be observed on stumps or dead trees. It is an irregularly shaped yellow-brown conk that will weep clear to yellow water-like drops on the top surface which dry to leave shallow depressions. As decay advances, several conks will fruit sometimes joining together to form large masses.
This fungus is moderately slow-progressing root rot, but will eventually lead to root failure. Trees become susceptible to windthrow and often none other than the appearance of the fungus will be noted when a tree fails. It is important to have an ISA Certified Arborist evaluate the tree if this fungus is observed. Testing for sound wood in the butt region of the tree is recommended. Those trees able to be retained should be periodically retested to track the progression of decay.