POLYMORPHISM IN PSILOCYBE MERDARIA

Abstract

Summary An isolate of the purple‐brown spored agaric Psilocybe merdaria (Fr.) Ricken, which had been collected on Mull, Scotland, was found to be unstable in its morphological characters when in pure culture. Apart from normal fruit‐bodies a series of forms developed, ranging from laterally stipitate to gasteromycetoid ones. The morphological characters of the two extreme forms, before and after several subcultures were made, are described. How these abnormal fruit‐bodies might amplify past and present theories on the origin of the Gasteromycetes is considered. The shape of the basidium in this one isolate was also found to be plastic and several deviations from the typical basidium are described. It is suggested that the origin of at least some types of pleurocystidia should be sought in modifications of the basidium. The use of the basidium as a major character in the classification of the Basidiomycetes is not discredited, but a closer relationship than previously expressed between the different groups of the higher fungi is argued. It is suggested that useful information might be obtained from the further study of teratological forms similar to those of P. merdaria whenever they are found in other higher fungi. In the field aberrant forms are not as rare as might be at first supposed.

How do Agaricomycetes shape their fruiting bodies? 1. Morphological aspects of development

“…Abnormal gasteroid and morchelloid forms were observed in nature for the agarics Galerina pseudomycenopsis and Psilocybe semilanceata Mart ın, 2001, 2003) and alongside to normal pileate-stipitate fruiting bodies in pure laboratory cultures of the agarics Volvariella bombycina (Chiu et al, 1989), Psilocybe coprophila (McKnight, 1953), Psilocybe mexicana (Singer, 1986) and Psilocybe merdaria (Watling, 1971). Abnormal morchelloid forms occur in nature also in Clitocybe, Collybia, Hydrocybe, and Tubaria species, Amanita pantherina, Hygrophorus nemoreus, and several other agarics, as well as in Boletales such as Paxillus involutus (Ulbrich, 1926(Ulbrich, , 1933aBenedix, 1967).…”

Dating the emergence of truffle-like fungi in Australia, by using an augmented meta-analysis

“…For example, the sequestrate Hydnangium sublamellatum can produce highly variable fruit-body morphologies, including agaricoid-like forms, although all forms lack active spore discharge (Bougher et al 1993). Conversely, agaricoid species may, rarely, form sequestrate fruit-bodies under certain conditions (Watling and Martín 2003;Braaten et al 2014) or in culture (Watling 1971). The stimulus that creates an adaptive benefit for agaricoid 'mushrooms' and other forms to evolve the sequestrate form is still unknown, but was originally thought to be related to a dry environment, including mountainous regions where rain may be seasonally absent (Thiers 1984).…”

Principles of Mushroom Developmental Biology

“…Fruit body polymorphism or developmental plasticity like this has been reported in various fungal species (Buller, 1922(Buller, , 1924Keyworth, 1942;Singer, 1975;van der Aa, 1997), but thorough studies have only been made on Psilocybe merdaria (Watling, 1971;Reijnders, 1977), Agaricus bisporus (Worsdell, 1915;Atkins, 1950;Reijnders, 1977;Flegg and Wood, 1985) and Volvariella bombycina (Chiu et al, 1989).…”