Fear the Fungi

TCBES graduate student studies toxic mushrooms found on UH Hilo campus

Copy Editor Rosannah Gosser Photos courtesy of Jeff Stallman

A recent study conducted by a graduate student in the University of Hawaiʻi at Hilo’s Tropical Conservation Biology and Environmental Sciences program focused on a species of poisonous mushroom known to be found on the UH Hilo campus. The student, Jeff Stallman, began his thesis project looking at species of mushrooms that grow on Hawaiʻi island, specifically a few genera in the family Agaricacea, including two species that contain potentially lethal chemical compounds if ingested by humans.

The genus of mushroom that Stallman has been studying incorporates about 400 species, and within those is a subsection for the species that contain amatoxins. “Up until now, we only knew of one species in Hawaiʻi that had these deadly toxins in them,” stated Stallman. “So as part of my project, I’ve found that these mushrooms are in the subgroup by using chemical, genetic, and morphological evidence to show that they also contain these deadly toxins.”

Stallman explained that here’s no evidence that anyone has ever actually eaten the species of mushrooms, but they do grow on campus, particularly in places like the botanical gardens or up at ʻImiloa Astronomy Center, where big piles of wood chips provide the perfect habitat for mushrooms: decaying organic matter mixed with a lot of moisture.

In his thesis project, Stallman documented two species of mushrooms containing poisonous chemicals called amatoxins. The first, Lepiota elaiophylla, can be spotted growing beneath ironwood trees in the districts of both Puna and Hilo. The second species, also belonging to the genus Lepiota, has not yet been named, but Stallman and his colleagues are currently working on a paper to give it an official scientific classification.

Another poisonous species of mushroom, Amanita marmorata, has been well-documented on all eight Hawaiian islands and can also be found on the UH Hilo campus. A medium-sized, mostly white mushroom, Amanita marmorata is mycorrhizal, meaning that it is “associated with the root systems of trees,” according to Professor Emeritus of Biology at UH Hilo and an advisor to Stallman’s thesis project, Dr. Don Hemmes, and can be found growing beneath Australian trees.

“The most common Australian tree on campus is the ‘paperbark’ or ‘bottle brush’ tree, so this mushroom is common on the campus under these trees in the fall,” explained Hemmes. Although not deadly, ingesting Amanita marmorata causes uncomfortable gastrointestinal issues such as vomiting and diarrhea.