Two friends

Two friends, never named — though one, we learn, is "devoid of imagination," so remember that as you read — are on a canoe trip down the Danube during its summer floods. This seems foolhardy enough, but then they decide to make camp on an island that turns out to be packed with monstrous, night-walking willow trees who definitely don't want them there. This story was reportedly one of H.P. Lovecraft's favorites, and we can see why.