Imperator Rhodopurpureus on:
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The oldrose bolete, ''Imperator rhodopurpureus'', is an inedible fungus of the genus ''
Imperator
The title of ''imperator'' ( ) originally meant the rough equivalent of ''commander'' under the Roman Republic. Later, it became a part of the titulature of the Roman Emperors as their praenomen. The Roman emperors generally based their autho ...
'', found under deciduous trees including oak
An oak is a hardwood tree or shrub in the genus ''Quercus'' of the beech family. They have spirally arranged leaves, often with lobed edges, and a nut called an acorn, borne within a cup. The genus is widely distributed in the Northern Hemisp ...
and beech
Beech (genus ''Fagus'') is a genus of deciduous trees in the family Fagaceae, native to subtropical (accessory forest element) and temperate (as dominant element of Mesophyte, mesophytic forests) Eurasia and North America. There are 14 accepted ...
in neutral soils. Initially described as ''Boletus rhodopurpureus'', it was transferred to the new genus ''Imperator
The title of ''imperator'' ( ) originally meant the rough equivalent of ''commander'' under the Roman Republic. Later, it became a part of the titulature of the Roman Emperors as their praenomen. The Roman emperors generally based their autho ...
'' in 2015. The bolete is considered critically endangered
An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of December 2023, of t ...
in the Czech Republic and endangered
An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching, inv ...
in the United Kingdom, reported most commonly from Berkshire and Hampshire, and typically very rare throughout, although up to a hundred fruiting bodies have been recorded at a few sites.
Description
The cap is cushion-like, up to 15 cm in diameter; faint yellow- or pink-buff when young, later flushing red from the rim and becoming blotched with yellow, red and olivaceous tones. The tubes are orange or red at first, then turning dark blue when cut. The spores are olive-brown. The stem is rather short, and sometimes very bulbous. The flesh is pale yellow, rapidly turning deep blue when cut. Bruises deep blue when handled, bruising blue at the slightest touch. A very rare bolete, B. xanthocyaneus, which has a predominantly yellow colouration, has also been reported, regularly fruiting along with normal-coloured oldrose boletes, such as from Windsor Great Park in the UK. This bolete was found to be a rare colour morph of I. rhodopurpureus based on DNA studiesOccurrence in the UK
The oldrose bolete is very rare in the UK, typically favouring old open woodland or parkland with plenty of sunlight on neutral soils, reported mainly from the south of England such as parts of the New Forest and Windsor Great Park.
Similar species and edibility
In the warmest regions of central and southern Europe the blood red-capped ''Rubroboletus dupainii
''Rubroboletus'' is a genus of bolete fungi in the family Boletaceae. It was circumscribed by Chinese mycologists in 2014 with '' Rubroboletus sinicus'' as the type species. Species are characterized by having a reddish cap surface, yellow tubes ...
''. It has also been regularly confused with the poisonous bilious bolete, ''Rubroboletus legaliae
''Rubroboletus legaliae'', previously known as ''Boletus splendidus'', ''B. satanoides'', and ''B. legaliae'' is a basidiomycete fungus of the family Boletaceae. It is Mushroom poisoning, poisonous, with predominantly gastrointestinal s ...
, from which it is distinguished by a much stronger bluing response when cut and handled. Commonly, the bilious bolete smells of hay or chicory, whereas the oldrose bolete has more acidic tones in its smell.
Oldrose bolete is poisonous when raw and is generally considered poisonous even when cooked.Mushrooms, R. Phillips and D. Reid, Macmillan 2006 The combination of being extremely uncommon and a confusion risk with the even more poisonous '' Rubroboletus'' genus makes this species one to avoid collecting for food.
References
* E. Garnweidner. ''Mushrooms and Toadstools of Britain and Europe''. Collins. 1994.External links
* * {{Taxonbar, from=Q882829 Fungi described in 1952 Fungi of Europe Boletaceae Fungus species