Cap 30-80 mm broad, campanulate to convex with a broad umbo, nonstriate, glabrous, hygrophanous, light brown to brown fading to greyish orange or orangish white in age. Gills adnexed to notched, extremely crowded, narrow, mazelike and constricted near Stem, orange white, spotted reddish brown in age. Stem 30-80 x 5-7 mm, equal or clavate, striate, pruinose to felted, orange white to pale brownish grey. Bitter taste. Spore Deposit cream-colored. Edibility: unknown.
The largest of the mushrooms in the native rain forest, this Rhodocollybia fruits in groups on fallen hapu’u tree ferns and in leaf mulch on the forest floor. The extremely crowded and narrow gills form a raised, collarlike region near the stem where they are forked and mazelike. This mushroom also grows directly out of cinder along Devastation Trail near Kilauea Iki in Hawai‘i Volcanoes National Park. Biweekly collecting over four years in several native forests on Hawai‘i indicate that R. laulaha has a very predictable cycle for fruitbody production. Mushrooms first appear profusely in July and continue. Close-up of the mazelike configuration of abundant production through December. Throughout the remainder of the year mushrooms are rarely formed even if the environmental conditions appear optimal. We have observed some mushrooms remaining fairly good, unputrefied condition for 3 to 4 weeks. Current data suggest that R. laulaha is a Hawaiian endemic species. Is: HA, KA, MA.