1) Fruiting body 
An acervulus (pl. acervuli) is a small asexual fruiting body that erupts through the epidermis of host plants parasitised by mitosporic fungi of the form order Melanconiales (Deuteromycota, Coelomycetes). It has the form of a small cushion at the bottom of which short crowded conidiophores are formed. The spores escape through an opening at the to...
A mass of closely clustered conidiophores and conidia not covered by fungal tissue, initially subcuticular or subepidermal but eventually exposed. 
an open, saucer-shaped asexual fruiting body found in fungi (kingdom Fungi). Always developed below the epidermis of the host tissue, it bears ...
<microbiology> A flat, often round mass of hyphae which carry spore-bearing parts called conidophores, acervuli are found in fungi belonging to the order Melanconiales. ... (09 Oct 1997) ... 
(ә-sur´vu-lәs) in imperfect fungi, a conidioma with a saucer-shaped surface where conidia form underneath a dome of tissue that ruptures at maturity to release the conidia.
A sub-epidermal, cushion-like mass of hyphae containing asexual condiophores that bear conidia formed by some imperfect fungi.
Type: Term Pronunciation: ă-ser′vyū-lŭs Synonyms: corpora arenacea, under corpus
[n] - small asexual fruiting body resembling a cushion or blister consisting of a mat of hyphae that is produced on a host by some fungi
noun small asexual fruiting body resembling a cushion or blister consisting of a mat of hyphae that is produced on a host by some fungi
(in certain fungi) an asexual fruiting body consisting of a mat of hyphae that give rise to short-stalked conidiophores.