They are mycorrhizal with conifers, meaning they have a symbiotic relationship with tree roots. You’ll frequently find them under Douglas firs or in mixed coastal forests.
This is the giveaway! The stem is usually yellow but heavily "flushed" or streaked with bright red or reddish-brown. boletus zelleri
Use a local field guide like the Field Guide to Mushrooms of Western North America or join a local mycological society to learn from experienced foragers. Fungi – the 'good' and the 'bad' - A Rocha Canada They are mycorrhizal with conifers, meaning they have
Native to western North America, Zeller’s Boletes are most common from . The stem is usually yellow but heavily "flushed"
Unlike many mushrooms with gills, boletes have a sponge-like underside made of tiny tubes. In the Zeller’s, these start out pale yellow and turn a deeper olive-yellow as the spores mature.