Macrolepiota zeyheri

Macrolepiota zeyheri has a complicated taxonomic history due to a series of minor errors and confusions in its classifications and published names. It was first described in 1843 by the British mycologist Miles Joseph Berkeley who classified it as Agaricus zeyheri or Agaricus (Lepiota) zeyheri. In 1848 the Swedish mycologist Elias Magnus Fries suggested that the species should be split into two based on the description he provided of differences between specimens he studied and the one originally described by Berkeley. Fries however did not suggest a name for this proposed species but in 1962 the German mycologist Rolf Singer classified it as Macrolepiota zeyheri and cited Fries as the original authority.'' This created an illegitimate name since Agaricus zeyheri had in fact been originally classified by Berkeley. The specific epithet zeyheri is named for the explorer and botanist who embarked on the South African expedition in which the first specimens of A. zeyheri were collected. As his name was given as M. Zeyher this has the potential to cause errors in modern optical character recognition when applied to scanned historical texts. Since so many species are named for him this can also create confusion with abbreviated species names, for instance L. zeyheri could refer to Lepiota zeyheri, Leucocoprinus zeyheri or Lentinus zeyheri.'' In his Sydowia paper, Singer used the author abbreviation 'Sing.' for himself rather than standard form recognised today of 'Singer'. This may present issues for automated systems designed to look for author citations in scanned documents and check them against the list of recognised names. In 1969 the Belgian mycologist Paul Heinemann discussed Macrolepiota zeyheri in his paper entitled Le genre Macrolepiota Sing. (Leucocoprineae) au Congo-Kinshasa however not only did he also use the Sing. abbreviation but he cited the wrong date for the Sydowia journal in which it was published. The citation which Heinemann used was Macrolepiota zeyheri (Berk.) Sing., Sydowia, 15: 67 (1952) however volume 15 of Sydowia was published in 1962. These cascading issues have resulted in some sources citing Heinemann as the authority on the species with a citation to Sydowia, which he did not write in. In 1887 Agaricus zeyheri (Berk.) was reclassified as Lepiota zeyheri by the Italian mycologist Pier Andrea Saccardo who also reclassified his Lepiota elegantula as a variant of it in the same year. In 1891 it was classified as Mastocephalus zeyheri by the German botanist Otto Kunze in his extensive proposed list of reclassifications. However no species remain within this genus. In 1943 it was reclassified as Leucocoprinus zeyheri by the German mycologist Rolf Singer and so in many sources Leucocoprinus zeyheri remained as a recognised species separately from Macrolepiota zeyheri. Heinemann's 1969 description of the species however does list Leucocoprinus zeyheri as a synonym. was a related species. In 1881 the Hungarian mycologist Károly Kalchbrenner and Peter MacOwan proposed the variant Agaricus (Lepiota) zeyheri var. telosus. In 1887 Pier Andrea Saccardo classified Agaricus verrucellosus as Lepiota zeyheri var. verrucellosus, whilst also recognising L. zeyheri var. telosa and describing L. zeyheri var. elegantula.'''' == Description ==

Historic Berkeley described Agaricus (Lepiota) zeyheri as follows: Cap: Around 15 cm wide, expanded with a wide umbo in the centre. The cap surface is white and smooth at the cap edges but cracking towards the centre whilst the umbo is brown with small warts. Gills: Free, broad and tan coloured from the spores but with colourless flesh when examined under a light. Stem: Around 18 cm tall and 2 cm thick running up into the flesh of the cap. Smooth and white and roughly equal in thickness across its length but with a bulbous base that is up to 4 cm thick. The stem is hollow but with slightly fibrous interior flesh. The persistent but movable stem ring is thick and large with membranous edges. with some of the former variants being reclassified as Chlorophyllum rhacodes and Macrolepiota excoriata. Saccardo describes L. zeyheri var. telosa as being 'equally spectacular' and notes large scales with brown lacerations with cobweb like formations on the cap. The colour is described as yellowish white or possibly white discolouring to yellow. L. zeyheri var. verrucellosa is described as being smaller than L. zeyheri with a slender white stem and bulbous base. The cap is described as umbonate and dotted with warts or brown scales. L. zeyheri var. elegantula is described as having reddish brown scales on the cap with a slender stem.'' The cap dries to creamy with brown scales and centre, the gills to ochre and the stem to yellowish grey. == Habitat and distribution ==

The specimens studied by Berkeley were collected from an expedition into South Africa GBIF records observations in the Congo and many more across South Africa. == Edibility ==

Macrolepiota zeyheri is reported to be an edible species however Heinemann notes that it was not consumed by the natives. == Etymology ==

Agaricus zeyheri was named for M. Zeyher, the African traveller and botanist who collected numerous specimens of various species on his expedition to the North interior of South Africa which began in November 1839. Zeyher was accompanied by Mr Burke who was a gardener in the employ of the 14th Earl of Derby, who funded the expedition entirely. The success of this expedition is perhaps best documented by the vast number of species which are named for Zeyher. == Similar species ==

• Macrolepiota mastoidea is described as looking extremely similar although its distribution is more typically European. M. zeyheri may be distinguished from it by its very wide gills which develop a pinkish colour with age however confusion is possible as the microscopic details are similar with only small difference between the size and shape of the spores. == References ==