Secotioid

Secotioid fungi are an intermediate growth form between mushroom-like hymenomycetes and closed bag-shaped gasteromycetes, where an evolutionary process of gasteromycetation has started but not run to completion. Secotioid fungi may or may not have opening caps, but in any case they often lack the vertical geotropic orientation of the hymenophore needed to allow the spores to be dispersed by wind, and the basidiospores are not forcibly discharged or otherwise prevented from being dispersed (e.g. gills completely inclosed and never exposed as in the secotioid form of Lentinus tigrinus)—note—some mycologists do not consider a species to be secotioid unless it has lost ballistospory. Secotioid fungi are an intermediate growth form between mushroom-like hymenomycetes and closed bag-shaped gasteromycetes, where an evolutionary process of gasteromycetation has started but not run to completion. Secotioid fungi may or may not have opening caps, but in any case they often lack the vertical geotropic orientation of the hymenophore needed to allow the spores to be dispersed by wind, and the basidiospores are not forcibly discharged or otherwise prevented from being dispersed (e.g. gills completely inclosed and never exposed as in the secotioid form of Lentinus tigrinus)—note—some mycologists do not consider a species to be secotioid unless it has lost ballistospory. Historically agarics and boletes (which bear their spores on a hymenium of gills or tubes respectively) were classified quite separately from the gasteroid fungi, such as puff-balls and truffles, of which the spores are formed in a large mass enclosed in an outer skin. However, in spite of this apparently very great difference in form, recent mycological research, both at microscopic and molecular level has shown that sometimes species of open mushrooms are much more closely related to particular species of gasteroid fungi than they are to each other. Fungi which do not open up to let their spores be dispersed in the air, but which show a clear morphological relation to agarics or boletes, constitute an intermediate form and are called secotioid. The word is derived from the name of the genus Secotium, which contains such species.