Fungi absorb nutrients using structures called hyphae, states the University of California Museum of Paleontology. Unlike plants, fungi cannot make their own food, so they must rely on other organisms for nutrition. Fungi are often saprophytes, ingesting dead organic material; some also act as parasites or mutualistic symbionts.
Hyphae look like a colorless mass of strings that together form the mycelium. The tip of the hypha exudes digestive enzymes that can break down food products present in the soil. Hyphae elongate at their tips when growing and can grow rapidly in the right medium. The mycelium is ideal for absorption of food because the hyphae possess a large surface area compared to their size. Some fungi have holes called septa between the hyphae that allow them to connect with one another and pass around substances. The hyphae break down food outside of the fungi before they absorb the nutrients. Fungi do not ingest their food; they live within their food and just absorb the nutrients that have already digested.
Parasitic fungi that prey on plants have specialized hyphae called haustoria that can poke through a plant's cell wall and procure food from the plant in this way. With symbiotic associations such as mycorrhizae, where fungi form a relationship with the roots of certain plants, the fungal hyphae absorb minerals and water from the soil.