Fungi Look Alikes.

Organisms or Structures That Look Like Fungi – But Aren’t


Eastern Gall Rust

Galls are abnormal vegetative growths that usually form when plants respond to the action of fungus, mites, or certain groups of insects. Although some kinds of fungi, for example the pine gall fungus (Cronartium quercuum), may actually be involved in the creation of galls, other kinds of galls have appearances that some observers may interpret to be fungal growths. Following are some common examples. 

 Several species of tiny gall wasps are responsible for the formation of a variety of “oak apple galls.” Oak apple galls have a thin but firm outer shell when dried, yet they are filled with a fibrous or spongy material that may look like a fungal growth. These galls are green when they appear in the spring, but turn to brown as they may remain on the tree into the fall. The causative agent of a large but light and very noticeable oak apple gall is a parasitic wasp, Biorhiza pallida. The fibrous strands filling the inside of the two-inch-wide gall have a fungus-like appearance.

Oak Gall1 Combo
Woolsower Gall Combo

Wool-sower galls appear on twigs of oaks and may be 1.5 to 2 inches long, but, unlike the oak-apple galls, they have no hardened outer covering. The woolly mass is some shade of white, speckled with reddish seed-like grains. Similar in form but not in color, woolly oak leaf galls form a dense wad of light brown “wool” attached usually to the midvein on the underside of an oak leaf (although occasionally they may be found on the lateral veins of the leaf). They are seen very commonly on oak leaves shed in the fall season, but usually are under an inch in length. Both wool-sower and woolly oak leaf galls are caused by parasitic gall wasps belonging to the genus Callirhytis.

Hickories also have small galls similar to the woolly oak leaf gall. The causative agent of the hairy, globular leaf galls are gall midges belonging to the genus Caryomyia

Peach Onion



A peculiar insect called a wax scale (scientifically Ceroplastes sp.) is related most closely to planthoppers, cicadas, and aphids. This group of insects uses piercing mouthparts to penetrate plant tissue and tap into the sugars contained in the sap. The adult females overwinter in the most visible stage, but they do not reach this stage until August or September. They are circular and reach a width of about 6 mm (1/4 inch), and they typically are bright white, pinkish or grayish in coloration. 

Some of the fluid material taken from the host plant comes through the body of the insect and is deposited as honeydew. Some of the sugary honeydew deposited around them may allow a growth of black, sooty mold fungus, so the otherwise whitish wax may become black blotched with an actual member of the fungi. Once tapped into the plant, the insect does not move, so the waxy buildup around the insect often resembles a fungal growth. 

Waxy Scale


Each kind of lichen is produced by the relationship of a specific fungus and a specific alga, which together produce a specific kind of lichen. A particular species of alga may be found in other kinds of lichens, so the taxonomic name given to each unique combination of alga and fungus really is just the name of the fungus. Most commonly, the type of fungus that is present in lichens, technically speaking, is a member of the Division Ascomycota and Class Ascomycete. Many lichens produce spores in stalked cup shaped appendages called apothecia. As with the British Soldier Lichen, the spores produced are in reality from the fungal partner. However, there is a smaller community of lichens known as basidiolichens in which the fungal partner is a member of the Division Basidiomycota and has the traditional form of a stalked mushroom. These lichen-forming fungi incorporate green algal cells in their tissues and often concentrate them in the cortical region of their sterile base.

Crustose Lichen

Lichens, of which 15,000 species are known to science, have scientific names as though each is a species of organism, but actually a lichen is comprised of a fungus and an alga supposedly living in a symbiotic relationship (both are benefited by living together.) The fungus cannot photosynthesize so it cannot create food from solar energy, but the alga can photosynthesize. 

The alga needs water but cannot hold it well, but the fungus is like a sponge more able to absorb and hold moisture. Thus, both species get their limiting resources from each other. There is some research, however, that leads to a conclusion that the relationship is more likely one of controlled parasitism of the alga by the fungus. Lichens are very common on tree trunks and bare rocks. They give the bark or stone a splotched, and sometimes very colorful, appearance. Also, fallen branches often are covered with lichens representing each of the three basic forms.

Foliose Lichen

Crustose lichens lie very flat, even at the edges, and have a crusty appearance – especially when dry. Foliose lichens look leafy (like foliage), and fruticose lichens are shrubby in appearance and stand freely away from the surface to which they are attached. Some authorities also refer to a forth growth form of lichen, called squamulose, which is described as being intermediate between foliose and crustose. Its shape is scale-like and is attached by the lower surface like tiny shingles.  

Some lichens are more greenish on one side and more grayish on the other. The green side has more algal cells, and the gray side more fungus. When a lichen produces spores, it means actually that the fungus is producing spores. The British Soldier lichen is particularly attractive due to the red spore-producing structures at the extremities. The scientific name for the lichen, Cladonia cristatella, actually is the technical name of the fungus. 

Beard Lichen

Some lichens also have interesting and memorable common names, such as: rock-pimples, earth wrinkles, angel’s hair, freckle pelts, fog fingers, dragon’s funnel, tar-jelly, and old man’s beard. 


 Indian Pipe (Monotropa uniflora) is a plant most closely related to the blueberry and rhododendron. Its flowers hang downward, the leaves are scale-like, and the plant reaches a height of 25 cm (10 inches). Lacking the green pigment, chlorophyll, live Indian Pipes are whitish in color. They turn black when dead, so the plant also has been called “corpse plant” and “ghost flower.” Indian Pipe grows from spring through fall in rich soils of shady woodlands – typically in areas with decaying plant material and often near decaying stumps. These conditions are right for many kinds of fungi, as well. Because the plant does not depend on photosynthesis to create food, it can grow in dark or very shady places – just like fungi. Technically, Indian Pipe is called a mycoheterotroph because this plant actually is parasitic on fungi! Fungi (molds and mushrooms) typically are decomposers that obtain nutrients by breaking down dead organic matter, but some kinds of fungi form a “mycorrhizal” relationship with the roots of trees. The fungus breaks down organic matter, part of which is absorbed by the roots of trees – therefore the tree is benefited. However, the relationship is reciprocal because some of the sugars produced by photosynthesis in the tree’s leaves are transported to the roots, where some is absorbed and used by the fungus. As a result, both fungus and tree are benefited by a mutual relationship. Energy for the Indian Pipe ultimately is parasitized from the mycorrhizal fungus. The roots of the Indian Pipe tap into the fungus and pick up some of the nutrients that the fungus had absorbed from the tree. Studies have shown that labeled carbon-dioxide taken in by a tree’s leaves was transported to the roots, absorbed by the fungus, then by the Indian Pipe. Thus, the life of the Indian Pipe depends on a three-way relationship with a fungus and another plant. The life strategy of the Indian Pipe makes it look vaguely like a fungus, and live where mushrooms may be common, but in fact it is a very unusual plant.


Photo Credit: Kory Roberts 

Slime Molds (Organisms formerly known as Fungi)

Mulches of bark or wood chips become beds of moist decaying plant matter, which is conducive to the growth of certain fungi. A variety of mushrooms may grow in those mulches, but organisms that look like molds also may grow there. Larger forms of these “slime molds,” which actually are not fungi, may cause unnecessary alarm and even calls to professionals such as veterinarians. 

Dog Vomit Combo

 Veterinarians sometimes get calls of concern because the substance may look like, to put it bluntly, dog vomit. The “dog vomit” slime mold (Fuligo septica) is one of the larger and more commonly seen slime molds in mulches. It begins as a bright yellow patch, and later becomes grayish. The mass is slimy in appearance and lies flat across the ground, so many people associate it with stomach problems in pets.

Slime molds have a strange and unusual life cycle. Although some references treat the organisms as members of the Kingdom Fungi (and some mushroom field guides contain images and text describing the organisms), they actually are not that closely related to fungi and now are placed in the Kingdom Protista. Plasmodial slime molds resemble the “blob” familiar in old horror movies, but they move like an amoeba at a slow rate of only about 1mm per hour. There is no cell wall, such as would be seen in plants, and a single membrane holds the mass together. In effect, the blob is one enlarged cell that includes a large number of nuclei (in most organisms, one cell contains one nucleus).  The enlarged cell is called a plasmodium because it is a mass of cell contents, or protoplasm. Most plasmodia are only a few millimeters in diameter, but some may reach over 30 cm (12 inches) in width. A plasmodium will develop “fruiting bodies” that produce spores, which is the way life begins for a plasmodial slime mold. A second group called cellular slime molds has minute cells that travel about singly, then respond to a chemical signal and join to form a structure similar to the plasmodium. This structure, however, contains numerous cells stuck to each other. 

Carnival Candy
Red Dot

 One common and brightly colored slime mold is known as “Wolf’s Milk” or “Pink Toothpaste” slime mold (Lycogala epidendrum). Often it is misidentified as a pink-colored puffball, although each individual is much smaller (usually under one cm, or 3/8 inch in width) than most fungal puffballs. When these pink spherical blobs are punctured, a pinkish slime often will squirt out, reminiscent of pink toothpaste. This slime mold is found typically on the side or top of large fallen trees.

Another often-encountered slime mold resembles brown hair because it has a plasmodium that transforms into a clustered mass of stalked sporangia. These are members of the genus Stemonitis, of which several species can be found in North America. As is common with slime molds, species of Stemonitis usually are seen growing on fallen logs and stumps. 

Mold Combo

Slime molds can be bright colors, such as red, yellow, or orange, and they also present in a variety of shapes. They are not harmful and there is no need for control measures (plus there are none that work). Despite the mold-like appearance and common name, they are not members of the fungi. 

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