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Anascocarp, orascoma (pl.:ascomata), is the fruiting body (sporocarp) of anascomycete phylum fungus. It consists of very tightly interwovenhyphae and millions of embeddedasci, each of which typically contains four to eightascospores. Ascocarps are most commonly bowl-shaped (apothecia) but may take on a spherical or flask-like form that has a pore opening to release spores (perithecia) or no opening (cleistothecia).[1][2][better source needed]
The ascocarp is classified according to its placement (in ways not fundamental to the basictaxonomy). It is calledepigeous if it grows above ground, as with themorels, while underground ascocarps, such astruffles, are termedhypogeous. The structure enclosing thehymenium is divided into the types described below (apothecium, cleistothecium, etc.) and this characteris important for the taxonomic classification of the fungus. Apothecia can be relatively large and fleshy, whereas the others are microscopic—about the size of flecks of ground pepper.
An apothecium (plural: apothecia) is a wide, open, saucer-shaped or cup-shaped fruit body. It is sessile and fleshy. The structure of the apothecium chiefly consists of three parts:hymenium (upper concave surface),hypothecium, andexcipulum (the "foot"). The asci are present in the hymenium layer. The asci are freely exposed at maturity. An example are the members ofDictyomycetes. Here the fertile layer is free, so that many spores can be dispersed simultaneously. Themorel,Morchella, an edible ascocarp, not a mushroom, favored by gourmets, is a mass of apothecia fused together in a single large structure or cap. The generaHelvella andGyromitra are similar.
A cleistothecium (plural: cleistothecia) is a globose, completely closed fruit body with no special opening to the outside. The ascomatal wall is calledperidium and typically consists of densely interwoven hyphae orpseudoparenchyma cells. It may be covered with hyphal outgrowth calledappendages. The asci are globose, deliquescent, and scattered throughout the interior cavity i.e. as inEurotium or arising in tufts from the basal region of ascocarps as inErysiphe. In this case the ascocarp is round with the hymenium enclosed, so the spores do not automatically get released, and fungi with cleistothecia have had to develop new strategies to disseminate their spores. The truffles, for instance, have solved this problem by attracting animals such aswild boars, which break open the tasty ascocarps and spread the spores over a wide area. Cleistothecia are found mostly in fungi that have little room available for their ascocarps, for instance those that live under tree bark, or underground like truffles.
Similar to a cleistothecium, a gymnothecium is a completely enclosed structure containing globose or pear-shaped, deliquescent asci. However, unlike the cleistothecium, the peridial wall of a gymnothecium consists of a loosely woven "tuft" of hyphae, often ornamented with elaborate coils or spines. Examples are theGymnoascus,Talaromyces and thedermatophyteArthroderma.
Perithecia are flask shaped structures opening by a pore orostiole (short papilla opening by a circular pore) through which the ascospores escape. Theostiolar canal may be lined by hair-like structures calledperiphyses. Theunitunicate asci are usually cylindrical in shape, borne on a stipe (stalk), released from a pore, developed from the inner wall of the perithecium and arise from a basal plectenchyma-centrum. Examples are members ofSphaeriales andHypocreales. Perithecia are also found inXylaria (Dead Man's Fingers, Candle Snuff),Nectria,Claviceps andNeurospora.
Sometimes the perithecia are "free" (individually visible from the outside), but in many species they are embedded in a dense sterile tissue of haploid cells called astroma (plural: stromata).[3] Some fungi have a shield-shaped layer called a clypeus over their perithecia.[4]
This is similar to a perithecium, but the asci are not regularly organised into a hymenium and they arebitunicate, having a double wall that expands when it takes up water and shoots the enclosed spores out suddenly to disperse them. Example species areApple scab (Venturia inaequalis) and the horse chestnut diseaseGuignardia aesculi.
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