Although fungi are closer to animals than plants, they had diverged from animals around 1 billion years ago, and are recognized as a separate kingdom. A Primer on fungi is here: https://www.cell.com/current-biology/fulltext/S0960-9822(09)01382-7?script=true. Fungi are very much understudied. For fungi the Hawaiʻi Fungi Project of citizen-scientists (https://www.Hawaiifungi.com/) has this note prominently displayed: “Only 7% of fungi have been discovered.”
Note: Some of the materials presented here are from a Biology of Fungi course at the University of Hawaiʻi. The web pages of the three instructors for that course are given below. If you want to learn about the fungi in some detail, that course is highly recommended.
For information see the laboratory pages for mycologists at UH:
From the University of Hawaiʻi Biology of Fungi class: A one line description of what fungi are and do: “Fungi are networks of cells optimized for penetration, extraction and movement of resources”. From a class lecture is the following list of characteristics of fungi.
The main groups of fungi are summarized here that includes the figure below: https://en.wikipedia.org/wiki/Fungus.
A complete indication of the groups of fungi is shown in the figure below which is taken from a 2019 Biological Reviews paper by M. Naranjo-Ortiz and T. Gabald which is here: https://onlinelibrary.wiley.com/doi/full/10.1111/brv.12510. (https://creativecommons.org/licenses/by-nc/4.0/legalcode).
A recent detailed classification of the fungi is in a 2020 paper in the journal Mycosphere with 148 authors Outline of fungi and fungi-like taxa that is here: http://mycosphere.org/pdf/MYCOSPHERE_11_1_8-1.pdf.
For a record of all fungi collections from Hawaiʻi the MycoPortal collections for Hawaiʻi is here: https://mycoportal.org/portal/collections/listtabledisplay.php?country=United%20States;USA;U.S.A.;United%20States%20of%20America&state=Hawaiʻi&occindex=1&sortfield1=Catalog%20Number&sortfield2=&sortorder=asc. For a species list only go here: https://mycoportal.org/portal/checklists/checklist.php?cl=27&pid=2. This page lists 400 species in Hawaiʻi.
For a historical study of fungi in Hawaiʻi see F. Stevens Fungi of Hawaiʻi (1925): http://hbs.bishopmuseum.org/pubs-online/pdf/bull19.pdf.
A good introduction to the types of mycorrhizal relationships is the Wikipedia page: https://en.wikipedia.org/wiki/Mycorrhiza.
Dr. Nicole Hynson at the University of Hawaiʻi studies mycorrhizal fungi and is a prominent authority. Her mycology laboratory website is: http://www2.Hawaii.edu/~nhynson/Hynson_Lab/Welcome.html. Her 2014 talk at Lyon is here: https://www.youtube.com/watch?v=aC2iUYocSZA&feature=youtu.be.
In the 2019 UH Biology of Fungi class it was noted that 92% of land plant families are mycorrhizal. Percentages for major groups were given as: Bryophytes – 71%, Pteridophyes – 93%, Gymnosperms – 100%, Angiosperms – 94%.
There are two main types of mycorrhizal relationhips with variations. From Wikipedia is this: “Mycorrhizas are commonly divided into ectomycorrhizas and endomycorrhizas. The two types are differentiated by the fact that the hyphae of ectomycorrhizal fungi do not penetrate individual cells within the root, while the hyphae of endomycorrhizal fungi penetrate the cell wall and invaginate the cell membrane. Endomycorrhiza includes arbuscular, ericoid, and orchid mycorrhiza, while arbutoid mycorrhizas can be classified as ectoendomycorrhizas. Monotropoid mycorrhizas form a special category.”
A good discussion with figures and photos describing the different types, including lichens, is here: http://www.botany.hawaii.edu/faculty/wong/BOT135/Lect26.htm.
Over 90% of endemic Hawaiian plant species consistently form arbuscular mycorrhizae (AM) in the field according to Gemma et al. (2002) published in the American Journal of Botany at: https://bsapubs.onlinelibrary.wiley.com/doi/pdf/10.3732/ajb.89.2.337. But only one native tree, pāpala kēpau (Pisonia sandwicensis) is known to associate with mushroom-forming fungi in an ectomycorrhizal relationship: https://www.dropbox.com/s/35vu0qoioqunm2n/Hynson%26Hayward2014.pdf?dl=0
For a discussion of the potential origins of mycorrhizae in Hawaiʻi have a look at the article by R. Koske et al. (1992) Mycorrhizae in Hawaiian angiosperms: a survey with implications for the origin of the native flora published in the American Journal of Botany. It can be found at this link (not available free): https://www.jstor.org/stable/2444994?seq=1.
A list of plant families and genera with mycorrihizal relationships and the type is here: https://mycorrhizae.com/wp-content/uploads/2017/03/Mycorrhizal-Status-of-Families-and-Genera-v1.6.pdf.
Some interesting recent papers are listed below.
One by J. Darcy et al. (2019) Fungal communities living within leaves of native Hawaiian dicots are structured by landscape-scale variables as well as by host plants is here: https://www.biorxiv.org/content/10.1101/640029v1.full.pdf.
Another by Amend et al. (2019) Phytobiomes are compositionally nested from the ground up is here: http://www.amendlab.com/files/Library_File/2019-05-22_01-56-34_pm_peerj-6609.pdf.
An ongoing study of the the microbiome of Waimea Valley by researchers at UH is described in a Science Magazine article titled No microbiome is an island, unprecedented survey of Hawaiian valley reveals is briefly described here: https://www.sciencemag.org/news/2019/08/no-microbiome-island-unprecedented-survey-Hawaiian-valley-reveals?utm_campaign=news_daily_2019-08-28&et_rid=17101647&et_cid=2964879.
Dr. Hemmes along with Dennis Desjardins authored the book Mushrooms of Hawaiʻi. They’ve identified more than four hundred species of mushrooms in Hawai‘i, sixty that are endemic, found nowhere else in the world: http://www.hanahou.com/pages/magazine.asp?Action=DrawArticle&ArticleID=1073&MagazineID=67&Page=1. An article about Don Hemmes (“the mushroom man”), emeritus professor at UH-Hilo and his work is here: http://www.hawaii.edu/malamalama/2002/01/Mushroom.html.