#2 - TREES? I thought this was a fungi blog! (1) - (5.22.25)
- May 22, 2025
- 6 min read
Kingdom Fungi is primarily known for its ecological role as a decomposer. Although this is true, fungi impressively form mutualistic mycorrhizal relationships with almost all plants. Fungal services are essential to most plants' lifestyles. Some plants have very specialized relationships with only one species of fungi. Likewise, many fungi only make ectomycorrhizal connections with specific groups of trees. For example, the false morel mushroom (Gyromitra esculenta) from Ascomycota is typically only found with conifer trees. However, some other macrofungi, such as the shaggy dry scale-head (Pholiota squarrosa) of Basidiomycota, form on live aspen or birch trees and act as a parasite to the tree. Many fungi across phyla are responsible for destructive parasitism in forests (Læssøe, 2013).
The relationship between plants, specifically trees, and fungi is incredibly interconnected, possibly even more than we know now. Additionally, information about a fungus' habitat and ecological roles, including which tree species it relates to, helps to make the best identification. So, as a mycologist, one needs to understand a fungus's ecological role to understand the species truly.
Every third week, I will compile a list of interesting trees I have found and try to explain any fungal relationships the species may have. I will also identify these trees using my super-handy book, Field Guide to Trees of North America, by the National Wildlife Federation. This first week, we will look into the sugarberry tree (Celtis laevigata), silktree (Albizia julibrissin), white mulberry tree (Morus alba), and tuliptree (Liriodendron tulipifera).
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TULIPTREE - Liriodendron tulipifera
I saw the flowers before I saw the leaves on this extraordinarily tall tree; bright yellow, magnolia-looking flowers were scattered across the trail floor. With six petals, a dome-shaped center, and an orange ring connecting each petal, they were easily identifiable as a tuliptree, also known as the yellow-poplar tree. The leaves are also distinct: untoothed, squarely lobed, and smooth (Kershner, 2008).
A study from Purdue University looked at the relationship of species from Glomeromycota (an early-diverging fungi division known for endomycorrhiza) with the tuliptree. The study, "Effects of Glomus fasciculatum or Glomus mosseae on Growth of Liriodendron tulipifera under High Fertility," conducted by Stephen D. Verkade and David F. Hamilton, grew tuliptrees from seeds inoculated with Glomeromycota species and compared them to tuliptrees that had not been inoculated with fungi to test how they would impact the growth rates of these trees. They found that both species of Glomeromycotes, G. fasciculatum and G. mosseae, significantly improved the growth of the tuliptree. Glomeromycota is interesting, as only fungi from this division form arbuscular or endomycorrhizal structures with plant roots. The difference between arbuscular mychorrhiza and ectomychorrhiza is that the hyphae of arbuscular fungi penetrate the plant cell walls to better facilitate the movement of materials between the fungus and plant using a structure called the arbuscle. In contrast, ectomycorrhizal fungi do not penetrate the plant during a mutualistic relationship (Verkade & Hamilton, 1985).
SUGARBERRY TREE - Celtis laevigata
The sugarberry tree (southern hackberry) within the elm family (Ulmaceae) and order Rosales is easily recognizable with an irregularly corked and bumpy bark and alternate leaves. Found across the Southeastern United States, they typically reside around river areas and are relatively common. The Celtis genus also includes two other trees; the northern hackberry and netleaf hackberry look almost identical and are found in other parts of the U.S. (Kershner, 2008.)
As previously discussed, fungi can parasitize trees and use their enzymes to degrade tough plant tissues like lignin. Researchers in the neighboring state of South Carolina have looked into the causes of the deaths of numerous Sugarberry trees due to armillaria root disease. The fungus Armillaria gallica is the cause of Armillaria root disease. Armillaria is commonly known as the honey fungus genus; many edible and well-known mushrooms are found within the genus. More specifically, A. gallica is commonly known as the bulbous honey fungus and is found on most continents. Until recent years, this root disease has migrated into more northern areas of the U.S. A possible reason is climate change; researchers suggest that increasing temperatures in northern regions have allowed for greater distribution of parasitic fungi, such as A. gallica (Cram, 2022).
SILKTREE - Albizia julibrissin
The silktree's bright purple spring flowers and odd leaf configuration make it hard to miss. It has bipinnate compound leaves resembling feathers and purple flowers in bunches with extended stamens. In summer, the silktree will produce long pods, as it is a part of the pea family (Fabaceae), and the order Fabales. Unfortunately, this beautiful tree is from Asia and Africa, making it invasive. Moreover, the species threatens many native plants in North Carolina and most of North America. It is from Asia and Africa (Kershner, 2008).
A study from the Anhui province of China (a location in which A. julibrissin is native) researched the common plant disease caused by Fusarium proliferatum, a fungus from the Pezizomycotina subdivision of Ascomycota. The study describes how Fusarium causes wilting and can cause death in adult trees. Fusarium specimens were collected from various plant tissues from trees that had died of the disease and then grown in agar (PDA). The fungal colonies produced conidia (asexual reproductive structures) with septate hyphae (hyphae with cell divisions). Researchers then inoculated healthy branches with the Fusarium, turning the branches black with a large and engrossing mycelium colony. Understanding such vicious fungal diseases can help to prevent devastating outbreaks that could affect the agroforestry and agriculture industries (Wang, 2019).
WHITE MULBERRY TREE - Morus alba
Also called the Russian mulberry, the white mulberry tree is easily identifiable by its blackberry-like fruits that drop along the ground to make black and purple splotches. Again, this is another non-native species from East Asia. As a note, it does look almost identical to the native red mulberry (Morus rubra) and sometimes hybridizes with the red mulberry, making identifications confusing (Kershner, 2008). However, I am more certain this is the white variety due to a difference in fruit size, color, and leaf texture. Not all IDs are perfect, and I completely accept that this could be a native red mulberry or a hybrid.
A study analyzing the fungal community in the soils of M. Alba and Alfalfa trees looked at the Ascomycota, Basidiomycota, and Mucoromycotina taxa to understand how intercropping practices can improve the properties of crop soil. The study highlights how the soil microorganisms contribute to the agroforestry industry's success. Such microorganisms are fungi, bacteria, and various protist supergroups that transform materials in the soil to make it easier for plants to use them, forming a mutualistic relationship. For example, the mulberry tree is known for harboring microorganisms (fungi are the microorganisms analyzed explicitly in this study) that fix nitrogen. The mulberry's collection of these fungi is helpful for agroforestry because not all plants can fix soil easily, and using mulberry trees could help alleviate nitrogen issues in crop soil. Using genetic sequencing to understand the makeup of the fungal community, researchers found both ectomycorrhizal members of Basidiomycota (12.32%) and Ascomycota (59.92%), but also endomycorrhizal species of Mucoromycotina that made up about 19% of the community. Mucoromycotina is a division of endomycorrhizal fungi, meaning that they can form mutualistic relationships with plants by inhabiting specific plant cells. Their classification is unknown, but they were once thought to be within Zygomycota. The study concluded by describing how the fungal community of soil is heavily correlated with the nutrients found in the soil (Zhang, 2019). Sources:
Cram, M., et al. (2022). First Report of Armillaria root disease of Celtis laevigata caused by A. gallica in South Carolina, USA. Plant Disease. doi:
Wang, C., et al. (2019). First Report of Silk Tree (Albizia julibrissin) Wilt Caused by Fusarium proliferatum in Anhui Province of China. Plant Disease, 103:11, 2947-2947. doi: https://doi.org/10.1094/PDIS-04-19-0876-PDN
Zhang, M., et al. (2019). Soil Physicochemical Properties and the Rhizosphere Soil Fungal Community in a Mulberry (Morus alba L.)/Alfalfa (Medicago sativa L.) Intercropping System. Forests, 10(2), 167. doi: https://doi.org/10.3390/f10020167
Verkade, S., Hamilton, D. (1985). Effects of Glomus fasciculatum or Glomus mosseae on Growth of Liriodendron tulipifera under High Fertility. Journal of Environmental Horticulture 3(3), 101–103. doi: https://doi.org/10.24266/0738-2898-3.3.101
Kershner, B., et al. (2008). National Wildlife Federation field guide to tree of North America. Sterling Pub. Co.
Læssøe, T., et al. (2013). Mushrooms: How to Identify and Gather Wild Mushrooms and Other Fungi. DK Publishing.
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