Monochrome micrograph showing Penicillium hyphae as long, straightforward, tube-like constructions a couple of micrometers across.

Conidiophores branch out along the side from the hyphae, ending in heaps of phialides on which circular condidiophores are orchestrated like dabs on a string.

Septa are faintly apparent as dull lines crossing the hyphae.

Most fungi develop as hyphae, which are tube shaped, string like constructions 2–10 µm in width and up to a few centimeters long.

Hyphae develop at their tips (apices); new hyphae are regularly shaped by rise of new tips along existing hyphae by an interaction called spreading, or every so often developing hyphal tips fork, bringing about two equal developing hyphae.

Hyphae likewise now and then breaker when they come into contact, a cycle called hyphal combination (or anastomosis). These development measures lead to the improvement of a mycelium, an interconnected organization of hyphae. Hyphae can be either septate or coenocytic.

Septate hyphae are partitioned into compartments isolated by cross dividers (interior cell dividers, called septa, that are framed at right points to the cell divider giving the hypha its shape), with every compartment containing at least one cores; coenocytic hyphae are not compartmentalized.

Septa have pores that permit cytoplasm, organelles, and some of the time cores to elapse through; a model is the dolipore septum in fungi of the phylum Basidiomycota.

Coenocytic hyphae are generally multinucleate supercells.

Numerous species have created particular hyphal structures for supplement take-up from living hosts; models remember haustoria for plant-parasitic types of most contagious phyla, and arbuscules of a few mycorrhizal fungi, which infiltrate into the host cells to burn-through nutrients.