An acervulus (pl. acervuli) is a small asexual fruiting body that erupts through the

epidermis The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and hypodermis. The epidermis layer provides a barrier to infection from environmental pathogens and regulates the amount of water rele ...

of host plants

parasitised Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...

by mitosporic fungi of the form

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...

Melanconiales ( Deuteromycota, Coelomycetes). It has the form of a small cushion at the bottom of which short crowded conidiophores are formed. The

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...

s escape through an opening at the top.

Sources

* Trigiano, Robert Nicholas, Mark Townsend Windham, Alan S. Windham. (2004) ''Plant Pathology: Concepts and Laboratory Exercises.'' CRC Press. pp. 11,129,137. Fungal morphology and anatomy Asexual reproduction {{botany-stub