Jack O’Lantern Mushroom

Omphalotus illudens

No, it is not time for Halloween, but it IS time for bright orange mushrooms to start popping out of the ground to do a little pre-holiday scaring. The Jack O’Lantern Mushroom is pretty distinctive, so you should have little trouble identifying this one. If a big patch of orange catches your eye in the local woods or neighborhood, be sure to stop and take a closer look.

You will find Jack O’Lanterns growing in groups, in late summer, often on stumps or places where trees have been cut down. That’s because this species grows on wood. The mushroom cap itself can be quite large—up to 8 inches in diameter, so a “patch” of jacks can measure two feet across at full size. The caps, stems, and gills in this species are orange. The large, fleshy gills run partially down the stem.

Legend has it that the gills of this mushroom are bioluminescent, such that you will see a greenish glow if you view them in the dark. I have actually seen this myself, having taken a large Jack to bed with me and then stayed awake long enough to see the mushroom glowing with my very own eyes. My husband thought this was a pretty silly thing to do, but once his eyes adjusted, he saw it too. Now he’s a believer.

Be aware that young versions of this mushroom are often mistaken for chanterelles, which are edible. Jack O’Lantern Mushrooms on the other hand, are toxic–and should never be consumed. One obvious way to tell these two kinds of mushrooms apart is by the gills. Jacks have non-forking, well-developed gills that can be separated and peeled off from the cap. Chanterelles have forking, “false gills”, which are really just ridges that cannot be separated from the cap. Also, Jacks tend to grow in clusters on wood, while chanterelles grow singly, or doubly in the soil.

Check out the photo gallery below. You can click on any photo to open a larger lightbox.