- Develop by SEPTATION and FRAGMENTATION of a hypha.
- May develop at the TIP OF A HYPHA or in an INTERCALARY (central) POSITION.
- In both cases, ALL LAYERS of the hyphal wall are involved in spore formation.
- A type of resting (survival) spore.
- Found in several groups of fungi (e.g. Zygomycota and mitosporic fungi).
- An intercalary (see diagram) or apical hyphal cell or compartment enlarges, rounds up and develops a thickened, often pigmented wall.
- Contain dense cytoplasm and nutrient storage compounds.
- All wall layers are involved in their formation.
- Become isolated from adjacent hyphal compartment(s) by the sealing of septal pores (if present).
- Usually develop under conditions of stress that are unfavourable for normal somatic growth.