Hyphae are the microscopic, thread-like structures that make up the mycelium of fungi. These tubular structures are the basic building blocks of the fungal body. Hyphae can vary in size and structure, but they generally consist of elongated cells with thin walls made of chitin, a complex polysaccharide.

Key characteristics of hyphae include:

Tubular Structure: Hyphae are typically long, cylindrical, and thread-like, resembling tiny tubes. The individual cells that make up the hyphae are called hyphal cells.

Septa or Nonseptate: Hyphae can be either septate or nonseptate. Septate hyphae are divided into individual cells by cross-walls called septa, which have pores allowing the passage of cytoplasm and organelles between cells. Nonseptate hyphae, also known as coenocytic, lack these septa and have a continuous, multinucleate cytoplasm along the entire length.

Growth and Branching: Hyphae grow by extending their tips, a process known as apical growth. They can also branch out, forming a network of interconnected hyphae. This branching allows the fungus to explore and colonize a larger area in search of nutrients.

Nutrient Absorption: The primary function of hyphae is to absorb nutrients. Fungi are heterotrophic organisms, meaning they obtain their nutrients from external sources. The hyphae secrete enzymes that break down complex organic matter into simpler compounds, and the nutrients are then absorbed through the hyphal cell walls.

Mycorrhizal Associations: In mycorrhizal symbiotic relationships with plants, hyphae extend into the soil and form associations with plant roots. This helps in nutrient uptake and exchange between the fungus and the plant.

Hyphae collectively form the mycelium, which is the vegetative part of the fungus. The mycelium is responsible for nutrient absorption, growth, and the overall life cycle of the fungus. In some cases, hyphae give rise to specialized structures, such as mushrooms or fruiting bodies, which are involved in the reproductive phase of the fungus.