''Rhodocollybia'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

Basidiomycete Basidiomycota () is one of two large divisions that, together with the Ascomycota, constitute the subkingdom Dikarya (often referred to as the "higher fungi") within the kingdom Fungi. Members are known as basidiomycetes. More specifically, Basi ...

mushroom. Species in this genus, formerly classified as a

subgenus In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between t ...

in ''

Collybia ''Collybia'' (in the strict sense) is a genus of mushrooms in the family Tricholomataceae. The genus has a widespread but rare distribution in northern temperate areas, and contains three species that grow on the decomposing remains of other mus ...

'', have fairly large

caps Caps are flat headgear. Caps or CAPS may also refer to: Science and technology Computing * CESG Assisted Products Service, provided by the U.K. Government Communications Headquarters * Composite Application Platform Suite, by Java Caps, a Java ...

(typically larger than broad), and have a pinkish-tinted

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 ...

. Microscopically, they are characterized by having

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...

s and

basidia A basidium () is a microscopic sporangium (a spore-producing structure) found on the hymenophore of fruiting bodies of basidiomycete fungi which are also called tertiary mycelium, developed from secondary mycelium. Tertiary mycelium is highly-c ...

that are

dextrinoid In mycology a tissue or feature is said to be amyloid if it has a positive amyloid reaction when subjected to a crude chemical test using iodine as an ingredient of either Melzer's reagent or Lugol's solution, producing a blue to blue-black staini ...

—staining deep reddish to reddish-brown with

Melzer's reagent Melzer's reagent (also known as Melzer's iodine reagent, Melzer's solution or informally as Melzer's) is a chemical reagent used by mycologists to assist with the identification of fungi, and by phytopathologists for fungi that are plant pathogens ...

when tested for amyloidity. ''Rhodocollybia'' species are commonly found in

temperate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout t ...

North America and Europe, and infrequently in Central and South America.

Taxonomy

The genus name ''Rhodocollybia'' was first used by

Rolf Singer Rolf Singer (June 23, 1906 – January 18, 1994) was a Germany, German-born mycologist and one of the most important Taxonomy (biology), taxonomists of gilled mushrooms (agarics) in the 20th century. After receiving his Ph.D. at the University ...

in 1939 to describe those species of ''

'' with a pink spore deposit; in later works he considered the genera equivalent (synonymous) and called them ''Collybia''. In 1997, Antonín and

Noordeloos Noordeloos is a town in the Dutch province of South Holland. It is a part of the municipality of Molenlanden, and lies about north of Gorinchem. In 2013, the town of Noordeloos had 1816 inhabitants. The built-up area of the town was 0.14 ...

studied various members of ''Collybia'' using

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

analysis, and reorganized the genus, dividing species into either ''Collybia'', ''

Gymnopus ''Gymnopus'' is a genus of fungus in the family Omphalotaceae. The genus has a widespread, cosmopolitan distribution and contains about 300 species. History and classification The type species for the Gymnopus, ''Gymnopus fusipes,'' dates bac ...

'', or ''Rhodocollybia''.

Description

The

of species in this genus are relatively large, often more than in diameter, convex in shape but in maturity flattening, or often developing a shallow umbo–a mound in the center of the cap. The surface of the cap is often uneven, and slimy or slippery ( lubricous) to the touch. The cap color can range from whitish to dark reddish brown. The

gills A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

are whitish to pinkish cream in color, and have an

adnexed In mycology, a lamella, or gill, is a papery hymenophore rib under the cap of some mushroom species, most often agarics. The gills are used by the mushrooms as a means of spore dispersal, and are important for species identification. The atta ...

attachment to the stem. The

stem Stem or STEM may refer to: Plant structures * Plant stem, a plant's aboveground axis, made of vascular tissue, off which leaves and flowers hang * Stipe (botany), a stalk to support some other structure * Stipe (mycology), the stem of a mushro ...

is usually long and thick (relative to the cap diameter), often more than long and at least thick; the color usually whitish or the same color as the gills. This type of agaric, collybioid mushroom has pale spore deposits which range from pinkish buff to pinkish cream. ;Microscopic features

Spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...

s in this species are typically spherical to ellipsoid in shape, and translucent (

hyaline A hyaline substance is one with a glassy appearance. The word is derived from el, ὑάλινος, translit=hyálinos, lit=transparent, and el, ὕαλος, translit=hýalos, lit=crystal, glass, label=none. Histopathology Hyaline cartilage is ...

). ''Rhodocollybia'' is characterized by having an endosporium (inner wall of the spore) that is

(staining yellowish or reddish-brown in

iodine Iodine is a chemical element with the symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , and boils to a vi ...

-containing solutions such as

), and sometimes

cyanophilous {{Short pages monitor