Until recently,
Deconica was generally considered to be
synonymous with
Psilocybe, and was originally named as a
subgenus of
Agaricus by
Worthington George Smith in 1870. It was later raised to generic level by
Petter Karsten in 1879. However, several
molecular studies published in the 2000s demonstrated that
Psilocybe, as it was defined then, was
polyphyletic. The studies supported the idea of dividing the genus into two
clades, one consisting of the bluing,
hallucinogenic species, and the other made of the non-bluing, non-hallucinogenic species. However, the generally accepted
lectotype (a specimen later selected when the original author of a taxon name did not designate a
type) of the genus as a whole was
Psilocybe montana, a non-hallucinogenic species; if those forms of the species in the study were to be segregated, it would leave the hallucinogenic clade without a valid name. To resolve this
taxonomical dilemma, it was proposed in 2005 to conserve the name
Psilocybe, with
P. semilanceata as the type, leaving the option to use
Deconica as the name for the non-hallucinogenic clade. The proposal was accepted unanimously by the
Nomenclature Committee for Fungi in 2009. Recently, it has been reported that the non-bluing
Psilocybe fuscofulva does not produce hallucinogenic compounds. Thus, non-hallucinogenic species are also covered by the genus
Psilocybe, not only
Deconica.
Deconica had previously been recognized as a separate genus by several authors, including
Rolf Singer in 1951, Dennis and Orton in 1960, and Horak in 1979. ==Species==