British distribution: Throughout Britain.
Identification and variation
Other colour variants of H. psittacina can be more problematic. Rarely it is bright blue and might then be confused with certain, rare Entoloma species, but its viscidity and white spore print would separate it from these. When yellow without a trace of green it might resemble H. glutinipes, but the latter is typically a brighter, purer yellow and has a very different structure to the gill tissues (much longer, non-inflated elements in the hymenophoral trama) under the microscope - reference to specialist literature such as Boertmann (2010) or Bon (1990) is needed. (There is also an H. ortoniana, which is "H. glutinipes" in the sense of several authors, and which does have a hymenophoral trama similar to H. psittacina but apparently differs macroscopically in being bright to orange yellow - these yellow waxcaps are rarely easy!).
Generally, however, the species that is most easily confused with H. psittacina is the closely related H. laeta. This is usually pinkish brown, grey at the stem apex, and lacks the green colours of H. psittacina, but flesh-coloured variants of the two species can look identical. The upland, flesh-coloured variant of H. psittacina, lacking any green on the stem, has been separated in the past as H. sciophanoides and Boertmann (2010) has given this varietal rank, as H. psittacina var. sciophanoides. As shown in the photograph above, intermediates exist.
Very rarely in Britain there is also a wholly yellow variant of H. laeta, var. lutea, which in the field again looks exactly like a yellow H. psittacina. The gills of H. laeta are pale and strongly decurrent, but the best macroscopic distinction, when needed, is that the gills of H. laeta have distinct, viscid, colourless edges, easily seen with a lens. (Also seen in H. vitellina, but this is a much more delicate, bright yellow species that should not be confused with H. psittacina or H. laeta.)
Finally, a wholly brick-red to red-brown variant of H. psittacina should be mentioned. This is usually regarded as a separate species, H. perplexa (= H. sciophana), but Boertmann considers it to be another colour form of H. psittacina, as H. psittacina var. perplexa. See above photograph of intermediate form.)
Current advice is that temporary handling of such material for purposes of identification is considered a reasonable defence, provided that the material is soon discarded, but the scientifically required preservation of voucher material to support research is illegal – the criminalisation of possession of one or two dried fruitbodies of a species in which some hundreds may be required for psychoactive effect is deemed more important than scholarship or the United Kingdom’s international obligation to foster knowledge in and conserve biodiversity. It appears that it may be considered acceptable to briefly hold material that is to be transferred to an institution (e.g. the herbaria of the Royal Botanic Gardens, Edinburgh or Kew) that is licensed to hold such material, but that is the limit of what is considered reasonable.
It will be noted that studio photographs shown above were taken at a time when common sense prevailed.