Editing Conidium (section)

===Structures for release of conidia===
Conidiogenesis is an important mechanism of spread of plant pathogens.  In some cases, specialized macroscopic fruiting structures perhaps 1 mm or so in diameter containing masses of conidia are formed under the skin of the host plant and then erupt through the surface, allowing the spores to be distributed by wind and rain.  One of these structures is called a '''conidioma''' (plural: '''conidiomata''').<ref>{{cite web|url=http://www.forestpathology.org/fungi.html#Asexual%20forms%20of%20Ascomycota |access-date=20 February 2023|year=2023|website=Forest Pathology|title=Fungi|author=James J. Worrall}}</ref><ref>{{cite journal |doi=10.1094/PHI-I-2001-0219-01|title=Illustrated Glossary of Plant Pathology|journal=The Plant Health Instructor|year=2001|last1=d'Arcy|first1=C.J.|last2=Eastburn|first2=D.M.|last3=Schumann|first3=G.L.|doi-access=}}</ref>

Two important types of conidiomata, distinguished by their form, are:
*'''pycnidia''' (singular: '''[[pycnidium]]'''), which are flask-shaped, and
*'''acervuli''' (singular: '''acervulus'''), which have a simpler cushion-like form.

Pycnidial conidiomata or ''pycnidia'' form in the fungal tissue itself, and are shaped like a bulging vase. The conidia are released through a small opening at the apex, the '''ostiole'''.

Acervular conidiomata, or ''acervuli'', are cushion-like structures that form within the tissues of a host organism:
*''subcuticular'', lying under the outer layer of the plant (the [[Plant cuticle|cuticle]]),
*''intraepidermal'', inside the outer cell layer (the [[Epidermis (botany)|epidermis]]),
*''subepidermal'', under the epidermis, or deeper inside the host.

Mostly they develop a flat layer of relatively short conidiophores which then produce masses of spores.  The increasing pressure leads to the splitting of the epidermis and cuticle and allows release of the conidia from the tissue.