''Hortiboletus rubellus'', commonly known as the ruby bolete, is a small, dainty, brightly coloured member of the family

Boletaceae The Boletaceae are a family of mushroom-forming fungi, primarily characterised by small pores on the spore-bearing hymenial surface (at the underside of the mushroom), instead of gills as are found in most agarics. Nearly as widely distributed ...

, with a reddish

cap A cap is a flat headgear, usually with a visor. Caps have crowns that fit very close to the head. They made their first appearance as early as 3200 BC. Caps typically have a visor, or no brim at all. They are popular in casual and informal se ...

and stipe, and yellow pores. Like many

bolete {{refimprove, date=July 2020 A bolete is a type of mushroom, or fungal fruiting body. It can be identified thanks to a unique mushroom cap. The cap is clearly different from the stem. On the underside of the cap there is usually a spongy surf ...

s, it stains blue when cut or bruised. It is found in

deciduous In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, ...

woodland in autumn. There is some question over its edibility, and it is reportedly of poor quality with a taste of soap. Until 2015, the species was known as ''Boletus rubellus''.

Taxonomy

''Boletus rubellus'' was one of the pored basidiomycetes to be placed in the genus ''

Xerocomus ''Xerocomus'' is a genus of poroid fungi related to ''Boletus''. Many mycologists did not originally recognize the distinction between the two genera and placed ''Xerocomus'' taxa in genus ''Boletus''. However, several molecular phylogenetic stu ...

'' in the past, and is still regarded as such in some texts. The previously commonly used binomial name ''Boletus versicolor'' (Rostk.), published in 1844, is now reduced to synonymy as it postdates the current name by German mycologist

Julius Vincenz von Krombholz Julius Vincenz von Krombholz (19 December 1782 – 1 November 1843) was a physician and mycologist born in Oberpolitz (today Horní Police, Czech Republic), northern Bohemia. He studied medicine at the University of Prague, receiving his doctora ...

which dates from 1836. Its present specific epithet ' is

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

for "somewhat red". The fungus was transferred to the new genus '' Hortiboletus'' in 2015, following molecular evidence indicating its genetic dissimilarity to ''Boletus''.

Description

It is a small

, with the

being rarely over in diameter. This cap is scarlet to raspberry red when young, with a dry velvety texture, often cracking in age. The extreme margin often has a pale yellow or white band around it, and it discolours darker and dirtier with age. The pores are small; pale yellow, and bruise slowly. Sometimes tapering, the stem is slender and long, and may reach . It is lemon yellow at the apex, but red elsewhere, and has a tendency to split or sheer vertically. The flesh is straw-coloured in the cap, and stains slowly blue over the tubes when cut. The flesh of the stem is pale yellow at the apex and yellow further down. At the stem base, the flesh may have a distinct spot of brick-red or orange. The tubes and pores are large and lemon-yellow, and may be greenish tinged when older. The

spore print 300px, Making a spore print of the mushroom ''Volvariella volvacea'' shown in composite: (photo lower half) mushroom cap laid on white and dark paper; (photo upper half) cap removed after 24 hours showing pinkish-tan spore print. A 3.5-centimeter ...

is olive. It smells pleasant, but indistinct, and is said to taste slightly soapy. Conflicting information on pore size in notable publications is a possible indication that there may be more than one species involved, both in Britain and in North America.

Distribution and habitat

Uncommon to rare in

Southern England Southern England, or the South of England, also known as the South, is an area of England consisting of its southernmost part, with cultural, economic and political differences from the Midlands and the North. Officially, the area includes ...

, occurring largely with oak (''

Quercus An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ...

''). It also appears in Europe, and the Eastern United States and Canada. A similar species noted as "cf versicolor" has been collected from Victoria in southeastern Australia.

Edibility

The species is edible, but often maggoty, and some sources describe the taste as soapy.

Similar species

Boletus bicolor ''Baorangia bicolor'', also known as the two-colored bolete or red and yellow bolete after its two-tone coloring scheme of red and yellow, is an edible fungus in the genus '' Baorangia''. It inhabits most of eastern North America, primarily ...

'' is almost identical, and ''B. campestris'' is very similar. Neither of these are reported in the

British Isles The British Isles are a group of islands in the North Atlantic Ocean off the north-western coast of continental Europe, consisting of the islands of Great Britain, Ireland, the Isle of Man, the Inner and Outer Hebrides, the Northern Isles, ...

. In Europe, this species is often mistaken for the similar '' B. armeniacus'' which does not show the same red coloration in the stem base. Other similar species include ''

Boletus chrysenteron ''Xerocomellus chrysenteron'', formerly known as ''Boletus chrysenteron'' or ''Xerocomus chrysenteron'', is a small, edible, wild mushroom in the family Boletaceae. These mushrooms have tubes and pores instead of gills beneath their caps. It i ...

'', ''B. coccyginus'', ''B. fraternus'', and ''B. truncatus''.

References