This month's fungus is an interesting parasite of trees, predominantly maple trees, and especially sugar maple, Acer saccharum . The only outward signs of the fungus are the shelf-like fruiting bodies that are produced in large overlapping clusters. The mushroom is not known to be poisonous, but it is bitter and too tough to eat. It's very sappy and gooey when you break it and is unusual looking on its underside. Instead of gills or pores, the fruiting body produces teeth, or downward hanging spines, that bear the basidiospores.
Teeth are another important way of increasing the surface area for bearing spores.
See my Introduction to the Kingdom Fungi for more information on surface area and fruiting bodies. The surface area section starts here . Most fungi produce an enormous number of spores because of their specialized nutritional niche in the environment. The chance of any one spore landing on a substrate on which it can actually grow is very small. I'm not sure how this applies, but maybe it refers to always needing a ladder to cut this down from the tree, since it's usually found fruiting fairly high up.