The March 2011 featured mushroom was...
Jack-O-Lanterns are fairly large wood-decaying mushrooms that occur at the base of stumps or growing from buried wood (roots) in lawns and forest floors. The Eastern Jack-O-Lantern is pumpkin-colored (bright orange to yellowish orange). The name Jack-O-Lanterns is even more appropriate since they also glow in the dark.
Jack-O-Lanterns have a cap that is 2 to 8 inches wide starting out convex but soon flattening then becoming funnel shaped with in-rolled margins and a small central knob. The stem is 2 to 8 inches long and ½ to ¾ inches wide. The gills are strongly decurrent and crowded. The entire mushroom is pumpkin-colored including the flesh. The spore print is pale cream.
Jack-O-Lanterns are quite poisonous causing severe gastrointestinal distress. One of the active poisons is muscarine; the same compound originally found in the fly agaric (Amanita muscaria) though not the major toxin of the fly agaric. Muscarine is present in sufficient quantities in certain Inocybe species so as to be fatal. Poisoning by Jack-O-Lanterns can lead to hospitalization to rehydrate and with a specimen that has a particularly large amount of muscarine to death.
Unfortunately, a young Jack-O-Lantern can be mistaken for an excellent edible, the chanterelle, particularly when growing from roots in lawns or on the forest floor. Chanterelles, of course, do not grow from stumps. Jack-O-Lanterns form clumps much more than chanterelles so that is way to distinguish them. A primary distinction is that Jack-O-Lanterns have true gills that are razor thin from top to bottom whereas chanterelles have false gills that form ridges which are wider at their base where they attach to the cap than at the free end. The flesh of the chanterelles is white to a slightly yellowish off-white whereas the flesh of the Jack-O-Lantern is pale orange to orange.