I have read On a Mushroom Day by Chris Baker and Alexandra Finkeldey before (or it did feel familiar at least). Maybe that was because I have read books about mushrooms/fungi before, so it might be a case of remembering that instead of this one. Either way, Baker’s book is a poetic story that could grab most readers. Even if you are not interested in edible (and not so edible) fungus, this is a nice book about the connection between us and nature.
The child and adult, while exploring the forest for mushrooms, experience more than the mushrooms. The child narrator also talks about the things happening underground and other things we might not be able to see. Plus, we find names of different plants and even a few myths along the way. One of the main themes is how the characters normalize the fact that hunting for the mushrooms is natural and you never know what you will find. It is also about how one should not do this solo, but have an educated adult along for the ride.
The illustrations are of course done in earthy tones and the details busy, but also are backdrop for the most part. You are still able to see the action (the child and adult bending over, looking, and so forth). They are not overly “mature” in their look, but are not childish either. They are set to engage the reader, but also allow the slow pacing of the actual journey taken to come into play.