King Oyster Mushrooms from Korea. Mycelium growing on wet, split, corrugated cardboard. Published December 10, 2015 at 940 × 1259 in Propagating King Oysters from Stem Butts King Oyster Mushrooms from Korea. Mycelium growing on wet, split, corrugated cardboard. King Oyster Mushrooms from Korea. Mycelium growing on wet, split, corrugated cardboard.