A Study of the Indigenous, Endemic, and Exotic Fungi in the Pu'u Maka'ala Natural Area Reserve in Volcano, Hawaii
The cool crisp air nipped at my face as I tugged on a pair of rubber boots over my blue jeans. I was about to go on a hike through a unique forest, the Pu‘u Maka‘ala Natural Area Reserve, to hunt for Hawaiian mushrooms and other fungi. My goal was to compare the numbers of indigenous, endemic, and exotic fungi in the Pu‘u Maka‘ala Natural Area Reserve. Pu‘u is a hill or volcanic cone, maka‘ala means to be alert or vigilant, and when searching for fungi in the dense Hawaiian rain forest, you must be very alert and have a keen eye. My mother and my sister, Mali‘o, were coming too, so we would have three pairs of eyes looking for fungi.
The Pu‘u Maka‘ala Natural Area Reserve is classified as a rain forest, with nearly 100 percent native plants. There are introduced weeds at the edges of the forest, but once you are in the forest, 90 percent of the vascular plants are endemic to Hawaii, and found nowhere else in the world. The forest is dominated by 20 to 30–foot–tall tree ferns (Cibotium glaucum), called hapu‘u in Hawaiian. These massive ferns have fallen and tangled trunks and dead fronds that make navigating off of the trail almost impossible. The tree ferns have trunks one to two feet in diameter made of a pithy, fiber–like material, and a woody core that is filled with a soft, opaque, jelly–like material. The fronds of this enormous fern are 10–15 feet in length, and the petioles are covered with a soft yellow fiber called pulu. Hawaiians stuffed the bodies of the dead with pulu after removing vital organs. This soft fiber was also collected during the late 1800s and exported to San Francisco to use for stuffing in mattresses and pillows. These long fronds drape down like a tent around the trunk when they die. Both the fern trunk and old fronds are excellent substrates for Hawaiian mushrooms and other fungi.
Scattered above the tree ferns is a medium–size to large tree called ‘ohi‘a (Metrosideros polymorpha). This tree has small leaves and brush-like blossoms called lehua in Hawaiian. These blossoms can range in color from red, the most common, to orange and yellow. White blossoms are very rare. These flowers are a favorite of Pele, the goddess of the volcano. When I was young and we needed rain to fill our water tank, my mother would send my brother and me outside to pick the lehua blossoms. It is believed the Pele cries when someone picks her flower, bringing rain to the area. ‘Ohi‘a seedlings often start growing off the tree fern trunks. Fallen branches of the ‘ohi‘a tree are also good substrates on which to look for fungal growth.
Other scattered endemic trees in the Pu‘u Maka‘ala area are ‘olapa (Cheirodendron trigynum), a small–to medium–size tree with broad leaves that dance in the wind and small bluish–purple berries that are a major component of a native bird‘s diet. The word ‘olapa was also once used in ancient Hawaii to give name to dancers who would imitate the graceful movements of the leaves. The berries were used by the Hawaiian people for dye in the making of kapa, or bark cloth, and the light wood was used as a fuel, even when green. Other trees found in the rain forest include pilo (Coprosma spp.), ‘olomea ( Perrottetia sandwicensis ), and kolea (Myrsine spp.), a tree that shares my name. Fungi are occasionally found on fallen logs of these species, too.
Hawaii is famous worldwide for its vascular plants, rain forest birds (the honeycreepers), and insects. People do not realize, however, that an integral part of these pristine forests is the fungi that are involved in the decomposition of organic substrates and the return of nutrients to the forest floor. Many mushrooms in Hawaii have not yet been named or even discovered because of their short fruiting life and remote locations. The first field guide to Hawaiian mushrooms will be published soon (Hemmes and Desjardin, 2002).
At the end of a short dirt road we parked the car. With my rubber boots, I was ready to trudge the muddy, wet trail through the dense rain forest of the Pu‘u Maka‘ala Reserve. In October I had hiked this trail collecting mushrooms with my science fair mentor, Dr. Don Hemmes, from the University of Hawaii at Hilo. I was excited about going out again. I packed my backpack with a notepad, sketchpad, pencil, pen, camera, pocket knife and specimen boxes, all necessary for identifying and collecting mushrooms. My plan was to walk along a transect (trail) through the forest and record each and every fungi I saw. Although I had been in the reserve once before, I was unsure of the exact route to take. My mom had talked Dr. Hemmes and had received instructions from him. We were to head into the reserve on the main trail, then take a right at the Y-fork, stay on the trail until we hit the Hawaii Volcanoes National Park fence line, then follow that back to our car.
We entered the Pu‘u Maka‘ala Natural Area Reserve alert and watchful for the wild mushrooms. I immediately saw dog tracks and footprints in the mud indicating that some pig hunters had been there. The pua‘a, or feral pig, likes to uproot native plants and create wallows in the mud in the forest. These wallows create pools where mosquitoes can breed. The mosquito then infects native birds with avian malaria. Pig hunting in these forests helps reduce these harmful effects.About 68 paces from the trailhead (18 inches in my pace), I spotted a tiny white mushroom growing out of a decaying Hawaiian raspberry (Rubus hawaiensis). This mushroom had a cap of only 1.5 mm in diameter and a stem 3–4 mm long. It was most likely one of the many yet-to-be-described Marasmius or Marasmiellus that grow in the wet forest. At least something was out.
Farther down the trail I came across the easily recognizable Hobsonia mirabilis, an imperfect fungus that forms small, 3–5 mm, white, jelly-like blobs on fallen, decaying hapu‘u fronds. While I was recording the data on this indigenous fungus, my sister found another species growing on decaying hapu‘u fronds. It was a small, cup-like fungus with no gills, another yet-to-be-identified species.
One of the native insects of the hapu‘u-o‘hia rain forest forms cocoons out of hapu‘u fibers and small leaves. On this cocoon, which hangs from the trunks of hapu‘u ferns, grow various fungi similar to the Cordyceps fungus, which grows on dead caterpillars and other insects. We found several of these on a fern trunk at 265 paces from the start of the trail. After reaching the intersection about 289 paces from the trailhead, we took a right onto the path that would take us to the fence. Thirteen paces from this intersection, we found another fungus growing on the larvae of some insect in the rain forest. This insect had made a cocoon out a section of hapu‘u frond, and a white, cauliflower-like fungus was growing from it. This part of the forest was very wet; there were numerous deep puddles of mud on the trail, and everything was extremely damp.
Along this section at 71 paces, my sister found a small mushroom (Crepidotus sp.) that had no stem and was almost flush with the pieces of hapu‘u fronds it was growing on. Only the thick beige gills of this 1–3 cm mushroom were seen. Looking at a cluster of these fungi, the thick rhizomorphic mycelium of the fungus became apparent. The networking characteristic of the mycelium was obvious. The strands of mycelium linked each and every fruiting body together on the tiny piece of bark.
A mushroom we encountered many times was Pholiota peleae. This endemic mushroom is characterized by its brown-to orange-colored cap and its mustard-yellow gills. The fruiting bodies of this Pholiota are solitary, and have a cap width of 3–5 cm and a stem length of 3–5 cm. The name of this endemic mushroom honors the Hawaiian goddess of the volcano, Pele. This mushroom was encountered at 198, 441, 483, 725, and 726 paces in section two, and at 829 and 985 paces in section three.Continuing on the trail to the fence, I found both immature and mature specimens of another endemic Hawaiian mushroom, Hygrocybe hapuuae. This mushroom gets its name from the substrate it grows on, hapu‘u. The two specimens I collected were found on hapu‘u leaf material and moss-covered hapu‘u logs. This small Hygrocybe has a light yellow stem measuring approximately one centimeter, and a white cap with a grayish center. The gills are white and barely attached to the stem.
While collecting and marking down the location of a Pholiota peleae , I noticed a small dark-gray mushroom growing from a fallen moss-covered hapu‘u that looked similar in size and shape to Hygrocybe hapuuae. This mushroom had a 1.5 cm gray stem, gray gills barely attached to the stem, and a dark gray, 0.5 cm diameter cap. This mushroom was later identified by my mentor as a Mycena sp., but as of yet it is undescribed because no one can find more than one fruiting body at a time.
I noticed a fallen, dead and decomposing ‘olapa tree a few yards from the trail. Knowing that there were wood-loving mushrooms in the forest, I decided to check it out. A piece of this ‘olapa tree was covered with a small, thin, bracket-like fungus with a smooth light-brown undersurface. The brackets were 1–2 mm thick, and the undersides and edges were covered with small hairy protrusions 1–3 mm long. These hairy protrusions were most likely part of this fungus‘ reproductive structures. This species was later identified as a Stereum species.
We continued on this trail until we came to a well-maintained fence that marked a boundary of Hawaii Volcanoes National Park. About 790 paces from the start of the fence line, my mom noticed a small stubby mushroom with a pointed golden-beige cap and a fat stem. I thought this was an immature Rhodocollybia laulaha, a common mushroom in the rain forest. My mom disagreed and insisted it was a different species and nicknamed it the "hobbit mushroom" because of the size and shape of the cap and its stubby little stem. Ten paces more on the trail we came across what I knew was surely a patch of Rhodocollybia laulaha. These mushrooms are quite easily distinguished by their large size and their relatively fine, crowded gills. The beige-colored cap easily measures 10–15 cm across, and its thick fibrous stem measures approximately 15–20 cm in length. The name for this endemic mushroom comes from the Hawaiian word laulaha, which means common and widespread. This mushroom is commonly encountered throughout the Hawaiian rain forest on fallen tree-fern trunks.
After we had crossed over a large ‘ohi‘a tree that fell over the National Park fence line, I noticed a small beige-colored mushroom growing from a piece of hapu‘u frond at 1,053 paces. This fungus had a cap 1 cm wide that was dark beige in the center. The gills were white and equally spaced and barely attached to the stem. The stem was white and 1 cm long. It was later identified as the endemic Mycena marasmielloides.
During the rest of our trek through the rain forest we found two of the more colorful species of endemic Hawaiian mushrooms. The first was, like most of the endemic mushrooms, growing on moss-covered hapu‘u. The cap was approximately 3 cm wide and a brilliant, radiant yellow. The gills were also the same shade of yellow as the stem. Being such a bright and radiant shade of yellow, this species was appropriately named Hygrocybe lamalama, which means "glowing like the sun" in Hawaiian. The next beautiful and interesting Hawaiian mushroom had a yellowish stem 4–5 cm long, and a pink cap 2–3 cm wide. The gills were also the same shade of pink and attached to the stem. The entire mushroom was viscid, or slimy, and extremely hard to grasp. This reminded me of a similar endemic mushroom, Hygrocybe pakelo, which means "slippery like a fish." But this mushroom was not H. pakelo but Hygrocybe noelokelani, one of the most beautiful of the Hawaiian endemic mushrooms. Noelokelani means "the pink rose in the mist or rain forest."
Also along the fence we found two common indigenous species, Rickenella fibula and Galerina decipiens. Rickenella fibula, the "moss agaric," has a petite orange cap 3 mm in diameter and a stem 8 mm in length. One of the identifying characteristics of this mushroom is its metallic smell. Galerina decipiens, which looks similar to Rickenella fibula, is lighter colored. It is also slightly larger, with a cap width of approximately 0.5–1 cm and a stem of approximately 2 cm. Both of these mushrooms were found on moss-covered trunks of hapu‘u.
We continued hiking along the fence, looking for a trail that would take us back to our car, but it became apparent that we had somehow missed it. We knew that if we followed the fence line we would return to the road that ran close to our home, but we were somewhat worried that it might get dark before then. We finally left the fence line to follow a well-traveled trail that took us through the University of Hawaii Experimental Station and back to the paved road, which we followed approximately one mile back to our car.
On this expedition, I found 16 different species of fungi. Of these, six were endemic, three were indigenous, 10 were unidentified, and none that I found was exotic. The lack of exotic fungi shows that the forest is extremely pristine, as fungi are one of the easiest spreading organisms. The 16 fungi I found are only a fraction of the many species of mushrooms and fleshy fungi to be identified in the native Hawaiian forests. Who knows what important antibiotics and pharmaceuticals they contain? Many of today‘s pharmaceuticals are derived from fungi; these new drugs are called mycopharmaceuticals. I plan to continue my studies of Hawaiian fungi in the future and to help in the possible discovery of the life-saving chemicals they contain.
Elbert, Samuel H. and Mary Kawena Pukui. Hawaiian Dictionary. Honolulu: University of Hawaii Press, 1986.
Hemmes, Don. Professor, University of Hawaii at Hilo. Many interviews by Kolea Zimmerman. Hilo, Hawaii, September-December 2001.
Juvik, James O. and Sonia P. Juvik. Atlas of Hawaii. Honolulu: University of Hawaii Press, 1998
Merlin, Mark D. Hawaiian Forest Plants. Honolulu: The Oriental Publishing Company, 1976.
Morrison, Boone. Journal of a Pioneer Builder. Honolulu: Hawaii Natural History Association, 1977.
Stone, Charles P. and Linda W. Pratt. Hawaii‘s Plants and Animals. Honolulu: Hawaii Natural History Association, 1994.
Copyright © 2002 American Museum of Natural History.
More About This Resource...
Less than 1 period
Supplement a study of biology with an activity drawn from this winning student essay.
- Send students to this online article, or print copies of the essay for them to read.
- Have them research this Hawaiian rain forest further, reporting on what they learn. If desired, you can have them start with the references cited at the end of the essay.
OriginYoung Naturalist Awards