Hymenium
Encyclopedia
The hymenium is the tissue layer on the hymenophore
of a fungal fruiting body where the cells develop into basidia
or asci
, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in others some cells develop into sterile cells called cystidia (basidiomycetes) or paraphyses
(ascomycetes). Cystidia are often important for microscopic identification. The subhymenium consists of the supportive hyphae from which the cells of the hymenium grow, beneath which is the hymenophoral trama
, the hyphae that make up the mass of the hymenophore.
The position of the hymenium is traditionally the first characteristic used in the classification and identification of mushrooms. Below are some examples of the diverse types which exist amongst the macroscopic Basidiomycota
and Ascomycota
.
Hymenophore
A hymenophore refers to the hymenium-bearing structure of a fungal fruiting body. Hymenophores can be smooth surfaces, lamellae, folds, tubes, or teeth....
of a fungal fruiting body where the cells develop into basidia
Basidium
thumb|right|500px|Schematic showing a basidiomycete mushroom, gill structure, and spore-bearing basidia on the gill margins.A basidium is a microscopic, spore-producing structure found on the hymenophore of fruiting bodies of basidiomycete fungi. The presence of basidia is one of the main...
or asci
Ascus
An ascus is the sexual spore-bearing cell produced in ascomycete fungi. On average, asci normally contain eight ascospores, produced by a meiotic cell division followed, in most species, by a mitotic cell division. However, asci in some genera or species can number one , two, four, or multiples...
, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in others some cells develop into sterile cells called cystidia (basidiomycetes) or paraphyses
Paraphyses
Paraphyses are part of the fertile spore-bearing layer in certain fungi. More specifically, paraphyses are sterile filamentous hyphal end cells composing part of the hymenium of Ascomycota and Basidiomycota interspersed among either the asci or basidia respectively, and not sufficiently...
(ascomycetes). Cystidia are often important for microscopic identification. The subhymenium consists of the supportive hyphae from which the cells of the hymenium grow, beneath which is the hymenophoral trama
Trama
Trama may refer to:* Trama , a genus of aphid* Trama , a mushroom's "flesh"* Trama , a Peruvian band* Spanish and Portuguese for plot* a medium access control protocol for sensor networks ....
, the hyphae that make up the mass of the hymenophore.
The position of the hymenium is traditionally the first characteristic used in the classification and identification of mushrooms. Below are some examples of the diverse types which exist amongst the macroscopic Basidiomycota
Basidiomycota
Basidiomycota is one of two large phyla that, together with the Ascomycota, comprise the subkingdom Dikarya within the Kingdom Fungi...
and Ascomycota
Ascomycota
The Ascomycota are a Division/Phylum of the kingdom Fungi, and subkingdom Dikarya. Its members are commonly known as the Sac fungi. They are the largest phylum of Fungi, with over 64,000 species...
.
- In agaricAgaricAn agaric is a type of fungal fruiting body characterized by the presence of a pileus that is clearly differentiated from the stipe , with lamellae on the underside of the pileus. "Agaric" can also refer to a basidiomycete species characterized by an agaric-type fruiting body...
s the hymenium is on the vertical faces of the gills. - In boleteBoleteA bolete is a type of fungal fruiting body characterized by the presence of a pileus that is clearly differentiated from the stipe, with a spongy surface of pores on the underside of the pileus...
s it is in a spongy mass of downward-pointing tubes. - In puffballPuffballA puffball is a member of any of several groups of fungus in the division Basidiomycota. The puffballs were previously treated as a taxonomic group called the Gasteromycetes or Gasteromycetidae, but they are now known to be a polyphyletic assemblage. The distinguishing feature of all puffballs is...
s it is internal. - In stinkhornStinkhornThe Phallaceae are a family of fungi, commonly known as stinkhorn mushrooms. Belonging to the fungal order Phallales, the Phallaceae have a worldwide distribution, but are especially prevalent in tropical regions. They are known for their foul smelling sticky spore masses, or gleba, borne on the...
s it develops internally and then is exposed in the form of a foul-smelling gel. - In cup fungi, it is on the concave surface of the cup.
- In teeth fungi, it grows on the outside of tooth-like spines.
External links
- IMA Mycological Glossary: Hymenium
- IMA Mycological Glossary: Subhymenium
- APSnet Illustrated Glossary of Plant Pathology: Hymenium Hymenium of an ascomycete, Monilinia fructicola
- Jack Murphy Mycological Images: Hymenium Hymenium of a basidiomycete, Russula laurocerasi
