Lactarius rupestris
Encyclopedia
Lactarius rupestris is a species of mushroom
in the Russulaceae
family. Described as a new species in 2010, it is known only from the semi-arid region in the National Park of Catimbau
of Brazil. The mushroom is characterized by a stout fruit body
with a smooth and sticky orange cap
up to 7 cm (2.8 in) in diameter. The gills on the underside of the cap are closely spaced and frequently anastomosed
. The stem
is 35 – long by 18 – thick. The mushrooms exude a sparse cream-colored latex
when cut or injured.
, in July of 2007. It was described as new to science in a 2010 Mycotaxon
publication by Felipe Wartchow of the Universidade Federal de Pernambuco. L. rupestris is one of 19 species of Lactarius
known from Brazil. The epithet rupestris refers to the campos rupestres
montane savanna—the ecoregion
where the type species was collected.
The authors note that the fungus does not readily fit into any of the infrageneric (i.e., below the level of genus) classification schemes outlined by previous authorities. For example, although L. rupestris has several characteristics that make the section Edules proposed by Annemieke Verbeken a somewhat close match, the taxon cannot be included because the surface of its cap is neither sufficiently areolate (cracked) nor dry enough, and its spores are excessively ornamented in comparison.
of L. rupestris is 60 –, concave to somewhat funnel-shaped, with a central depression. Its color is orange at the center to brownish-orange towards the margin. The cap surface is somewhat sticky, and the texture is either smooth to slightly cracked. It has an indistinct layer of matted mycelial "hairs". The margin lacks striations and grooves, and is curled inward slightly. The gills are slightly decurrent
(running slightly down the length of the stem), cream-salmon
in color, and crowded closely together. They are up to 3 mm (0.118110236220472 in) broad and are frequently branched. The gill edges are smooth, and the same color as the gill face. There are several tiers of lamellulae (short gills that do not extend fully from the cap margin to the stem) interspersed between the gills. The stem
is 35 – long by 18 – thick, centrally attached to the stem, cylindrical, and tapers slightly near the base. It is pale ochraceous
-salmon, and slight longitudinal ribs can be seen with a magnifying glass. The flesh
is spongy, pale yellow-ochre in the cap, and cream-yellow in the stem. The latex
is cream-colored to roughly the same color as the gills, and not abundant.
s are roughly ellipsoid to roughly spherical, and typically measure 7–8.5 by 6–7 µm
. The ornamentation on the spore surface is amyloid
(staining blue to blue-black in Melzer's reagent
) and finely wart-like, with each wart ranging to 0.5–0.7 µm high. The warts are interconnected by thin ridges, but the ridges do not form a complete reticulum. The hilar appendage (the part of a spore once attached to the basidium via the sterigma
) ranges in shape from narrowly obtuse to somewhat conical; the plage
is not very distinct, but has an amyloid spot. The basidia (spore-bearing cells in the hymenium
) are 35–50 by 8–11 µm, club-shaped, and bear mainly four, but sometimes two long (6–10 µm) sterigma
ta.
Pseudopleurocystidia are very scarce on the gill faces; when present, they are thin-walled, 170 µm long by 24 µm wide, with brownish refractive contents, and arise from deep in the tissue of the hymenophore
. The edge of the gill is sterile (lacking basidia), and has marginal cells that are 30–45 by 4–6 µm, cylindrical to somewhat sinuous (curvy), thin-walled, and hyaline
(translucent). The tissue of the cap has abundant sphaerocysts (spherical, swollen cells common to the Russulaceae
) and measure 25–65 by 24–50 µm, in addition to filamentous hyphae that are up to 10 µm wide. Lactiferous (latex-containing) hyphae are common in the cap tissue. They are up to 15 µm wide with a longitudinal orientation. Although they diverge from the trama somewhat (spreading out from the center of the gill), they do not form projecting pseudocystidia. The subhymenium (the layer of cells directly under the hymenium) is made of club-shaped to nearly spherical cells that are 16–27 by 9–17 µm. The tissue that comprises the hymenophore is made of several parts. It contains abundant, nearly isodiametric (17–25 by 13–18 µm) cells, and filamentous hyphae that measure 3.5–6.5 µm; lactiferous hyphae are frequent, up to 7–12 µm wide, straight and only occasionally branching. The cap cuticle
is a trichoderm—meaning the outermost hyphae emerge roughly parallel, like hairs, perpendicular to the cap surface. It is up to 140 µm thick and comprises two layers. The upper layer, the suprapellis, is made of plentiful, colorless hyphae that are 20–51 by 4–6 µm, thin-walled (up to 0.5 µm), and range in shape from obtuse to somewhat acute to knob-like or pear-shaped. The lower layer of the cap cuticle, the subpellis, is made of both plentiful hyphae that are 3–8 µm wide and somewhat more inflated colorless cells up to 10–18 µm wide. Lactarius rupestris does not have clamp connection
s in its hyphae.
subfamily Mimosoideae
and others) in a semi-arid region, after heavy precipitation. The species is known only from the type locality in Vale do Catimbau National Park
in Brazil, in the state of Pernambuco
. It fruits at an elevation of 900 to 1000 m (2,952.8 to 3,280.8 ft). This is part of the biodiverse cerrado
ecoregion, in an area known as the campos rupestres
. Although the fungus is suspected to be mycorrhiza
l (like all Lactarius
), there was a wide diversity of plant species growing in the open, dry forest where the mushroom was found (including members of the tree families Euphorbiaceae
, Fabaceae
, Myrtaceae
, Nyctaginaceae
, and Polygonaceae
—all known to form mycorrhizal associations), so the authors did not speculate on any specific interactions.
Mushroom
A mushroom is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground on soil or on its food source. The standard for the name "mushroom" is the cultivated white button mushroom, Agaricus bisporus; hence the word "mushroom" is most often applied to those fungi that...
in the Russulaceae
Russulaceae
The Russulaceae are a family of fungi in the order Russulales. According to a 2008 estimate, the family contains 1243 species. Its species typically have fruit bodies with friable, chalk-like stalks, that break with a distinct crack, somewhat like a carrot but with porous flesh...
family. Described as a new species in 2010, it is known only from the semi-arid region in the National Park of Catimbau
Vale do Catimbau National Park
The Vale do Catimbau National Park is a national park of Brazil, located in the city of Buíque in the state of Pernambuco. The Catimbau Valley or Vale do Catimbau in Portuguese is Brazil's 2nd largest archaeological site. Among its natural attractions there are beautiful canyons, over 2,000 caves,...
of Brazil. The mushroom is characterized by a stout fruit body
Basidiocarp
In fungi, a basidiocarp, basidiome or basidioma , is the sporocarp of a basidiomycete, the multicellular structure on which the spore-producing hymenium is borne. Basidiocarps are characteristic of the hymenomycetes; rusts and smuts do not produce such structures...
with a smooth and sticky orange cap
Pileus (mycology)
The pileus is the technical name for the cap, or cap-like part, of a basidiocarp or ascocarp that supports a spore-bearing surface, the hymenium. The hymenium may consist of lamellae, tubes, or teeth, on the underside of the pileus...
up to 7 cm (2.8 in) in diameter. The gills on the underside of the cap are closely spaced and frequently anastomosed
Anastomosis
An anastomosis is the reconnection of two streams that previously branched out, such as blood vessels or leaf veins. The term is used in medicine, biology, mycology and geology....
. The stem
Stipe (mycology)
thumb|150px|right|Diagram of a [[basidiomycete]] stipe with an [[annulus |annulus]] and [[volva |volva]]In mycology a stipe refers to the stem or stalk-like feature supporting the cap of a mushroom. Like all tissues of the mushroom other than the hymenium, the stipe is composed of sterile hyphal...
is 35 – long by 18 – thick. The mushrooms exude a sparse cream-colored latex
Latex
Latex is the stable dispersion of polymer microparticles in an aqueous medium. Latexes may be natural or synthetic.Latex as found in nature is a milky fluid found in 10% of all flowering plants . It is a complex emulsion consisting of proteins, alkaloids, starches, sugars, oils, tannins, resins,...
when cut or injured.
Discovery and classification
The species was found in the Brazilian semi-arid region in the National Park of CatimbauVale do Catimbau National Park
The Vale do Catimbau National Park is a national park of Brazil, located in the city of Buíque in the state of Pernambuco. The Catimbau Valley or Vale do Catimbau in Portuguese is Brazil's 2nd largest archaeological site. Among its natural attractions there are beautiful canyons, over 2,000 caves,...
, in July of 2007. It was described as new to science in a 2010 Mycotaxon
Mycotaxon
Mycotaxon is a peer-reviewed scientific journal that publishes papers on the nomenclature and taxonomy of the fungi, including lichens....
publication by Felipe Wartchow of the Universidade Federal de Pernambuco. L. rupestris is one of 19 species of Lactarius
Lactarius
Lactarius is a genus of mushroom-producing fungi. The genus, collectively known commonly as milk-caps, are characterized by the fact that they exude a milky fluid if cut or damaged...
known from Brazil. The epithet rupestris refers to the campos rupestres
Campos Rupestres montane savanna
The Campos Rupestres montane savanna is a montane subtropical savanna ecoregion of eastern Brazil, a part of the cerrado ecoregion.-Setting:The ecoregion lies between 700 and 2000 meters elevation, forming several discontinuous enclaves in the Serra do Espinhaço, Serra da Mantiqueira, Serra dos...
montane savanna—the ecoregion
Ecoregion
An ecoregion , sometimes called a bioregion, is an ecologically and geographically defined area that is smaller than an ecozone and larger than an ecosystem. Ecoregions cover relatively large areas of land or water, and contain characteristic, geographically distinct assemblages of natural...
where the type species was collected.
The authors note that the fungus does not readily fit into any of the infrageneric (i.e., below the level of genus) classification schemes outlined by previous authorities. For example, although L. rupestris has several characteristics that make the section Edules proposed by Annemieke Verbeken a somewhat close match, the taxon cannot be included because the surface of its cap is neither sufficiently areolate (cracked) nor dry enough, and its spores are excessively ornamented in comparison.
Description
The capPileus (mycology)
The pileus is the technical name for the cap, or cap-like part, of a basidiocarp or ascocarp that supports a spore-bearing surface, the hymenium. The hymenium may consist of lamellae, tubes, or teeth, on the underside of the pileus...
of L. rupestris is 60 –, concave to somewhat funnel-shaped, with a central depression. Its color is orange at the center to brownish-orange towards the margin. The cap surface is somewhat sticky, and the texture is either smooth to slightly cracked. It has an indistinct layer of matted mycelial "hairs". The margin lacks striations and grooves, and is curled inward slightly. The gills are slightly decurrent
Decurrent
Decurrent is a term used in botany and mycology to describe plant or fungal parts that extend downward.In botany, the term is most often applied to leaf blades that partly wrap or have wings around the stem or petiole and extend down along the stem...
(running slightly down the length of the stem), cream-salmon
Salmon (color)
Salmon a range of pale pinkish-orange to light pink colors, named after the color of salmon flesh.The web color salmon is displayed at right.The first recorded use of salmon as a color name in English was in 1776...
in color, and crowded closely together. They are up to 3 mm (0.118110236220472 in) broad and are frequently branched. The gill edges are smooth, and the same color as the gill face. There are several tiers of lamellulae (short gills that do not extend fully from the cap margin to the stem) interspersed between the gills. The stem
Stipe (mycology)
thumb|150px|right|Diagram of a [[basidiomycete]] stipe with an [[annulus |annulus]] and [[volva |volva]]In mycology a stipe refers to the stem or stalk-like feature supporting the cap of a mushroom. Like all tissues of the mushroom other than the hymenium, the stipe is composed of sterile hyphal...
is 35 – long by 18 – thick, centrally attached to the stem, cylindrical, and tapers slightly near the base. It is pale ochraceous
Ochre
Ochre is the term for both a golden-yellow or light yellow brown color and for a form of earth pigment which produces the color. The pigment can also be used to create a reddish tint known as "red ochre". The more rarely used terms "purple ochre" and "brown ochre" also exist for variant hues...
-salmon, and slight longitudinal ribs can be seen with a magnifying glass. The flesh
Trama (mycology)
In mycology trama is a term for the inner, fleshy portion of a mushroom's basidiocarp, or fruit body. It is distinct from the outer layer of tissue, known as the pileipellis or cuticle, and from the spore-bearing tissue layer known as the hymenium....
is spongy, pale yellow-ochre in the cap, and cream-yellow in the stem. The latex
Latex
Latex is the stable dispersion of polymer microparticles in an aqueous medium. Latexes may be natural or synthetic.Latex as found in nature is a milky fluid found in 10% of all flowering plants . It is a complex emulsion consisting of proteins, alkaloids, starches, sugars, oils, tannins, resins,...
is cream-colored to roughly the same color as the gills, and not abundant.
Microscopic characteristics
The sporeSpore
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...
s are roughly ellipsoid to roughly spherical, and typically measure 7–8.5 by 6–7 µm
Micrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...
. The ornamentation on the spore surface is amyloid
Amyloid (mycology)
In mycology the term amyloid refers to a crude chemical test using iodine in either Melzer's reagent or Lugol's solution, to produce a black to blue-black positive reaction. It is called amyloid because starch gives a similar reaction, and that reaction for starch is also called an amyloid reaction...
(staining blue to blue-black in Melzer's reagent
Melzer's Reagent
Melzer's reagent is a chemical reagent used by mycologists to assist with the identification of fungi.-Composition:...
) and finely wart-like, with each wart ranging to 0.5–0.7 µm high. The warts are interconnected by thin ridges, but the ridges do not form a complete reticulum. The hilar appendage (the part of a spore once attached to the basidium via the sterigma
Sterigma
thumb|right|The sterigmata is the slender extension that connects the spore to the basidia .A sterigma is an extension of the basidium consisting of a basal filamentous part and a slender projection with a spore at the tip...
) ranges in shape from narrowly obtuse to somewhat conical; the plage
Plage (mycology)
A plage is a clear, unornamented area on the basal area of an otherwise ornamented spore. Characteristic of spores from the euagaric genus Galerina.-Images:* - line drawing* - photo...
is not very distinct, but has an amyloid spot. The basidia (spore-bearing cells in the hymenium
Hymenium
The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in others some cells develop into sterile cells called cystidia or...
) are 35–50 by 8–11 µm, club-shaped, and bear mainly four, but sometimes two long (6–10 µm) sterigma
Sterigma
thumb|right|The sterigmata is the slender extension that connects the spore to the basidia .A sterigma is an extension of the basidium consisting of a basal filamentous part and a slender projection with a spore at the tip...
ta.
Pseudopleurocystidia are very scarce on the gill faces; when present, they are thin-walled, 170 µm long by 24 µm wide, with brownish refractive contents, and arise from deep in the tissue of the hymenophore
Hymenophore
A hymenophore refers to the hymenium-bearing structure of a fungal fruiting body. Hymenophores can be smooth surfaces, lamellae, folds, tubes, or teeth....
. The edge of the gill is sterile (lacking basidia), and has marginal cells that are 30–45 by 4–6 µm, cylindrical to somewhat sinuous (curvy), thin-walled, and hyaline
Hyaline
The term hyaline denotes a substance with a glass-like appearance.-Histopathology:In histopathological medical usage, a hyaline substance appears glassy and pink after being stained with haematoxylin and eosin — usually it is an acellular, proteinaceous material...
(translucent). The tissue of the cap has abundant sphaerocysts (spherical, swollen cells common to the Russulaceae
Russulaceae
The Russulaceae are a family of fungi in the order Russulales. According to a 2008 estimate, the family contains 1243 species. Its species typically have fruit bodies with friable, chalk-like stalks, that break with a distinct crack, somewhat like a carrot but with porous flesh...
) and measure 25–65 by 24–50 µm, in addition to filamentous hyphae that are up to 10 µm wide. Lactiferous (latex-containing) hyphae are common in the cap tissue. They are up to 15 µm wide with a longitudinal orientation. Although they diverge from the trama somewhat (spreading out from the center of the gill), they do not form projecting pseudocystidia. The subhymenium (the layer of cells directly under the hymenium) is made of club-shaped to nearly spherical cells that are 16–27 by 9–17 µm. The tissue that comprises the hymenophore is made of several parts. It contains abundant, nearly isodiametric (17–25 by 13–18 µm) cells, and filamentous hyphae that measure 3.5–6.5 µm; lactiferous hyphae are frequent, up to 7–12 µm wide, straight and only occasionally branching. The cap cuticle
Pileipellis
thumb|300px||right|The cuticle of some mushrooms, such as [[Russula mustelina]] shown here, can be peeled from the cap, and may be useful as an identification feature....
is a trichoderm—meaning the outermost hyphae emerge roughly parallel, like hairs, perpendicular to the cap surface. It is up to 140 µm thick and comprises two layers. The upper layer, the suprapellis, is made of plentiful, colorless hyphae that are 20–51 by 4–6 µm, thin-walled (up to 0.5 µm), and range in shape from obtuse to somewhat acute to knob-like or pear-shaped. The lower layer of the cap cuticle, the subpellis, is made of both plentiful hyphae that are 3–8 µm wide and somewhat more inflated colorless cells up to 10–18 µm wide. Lactarius rupestris does not have clamp connection
Clamp connection
A clamp connection is a structure formed by growing hyphal cells of certain fungi. It is created to ensure each septum, or segment of hypha separated by crossed walls, receives a set of differing nuclei, which are obtained through mating of hyphae of differing sexual types...
s in its hyphae.
Habitat and distribution
The mushroom was found buried with up to two-thirds of the stem in sandy soil near several shrubs (FabaceaeFabaceae
The Fabaceae or Leguminosae, commonly known as the legume, pea, or bean family, is a large and economically important family of flowering plants. The group is the third largest land plant family, behind only the Orchidaceae and Asteraceae, with 730 genera and over 19,400 species...
subfamily Mimosoideae
Mimosoideae
Mimosoideae is a subfamily of the flowering plant family Fabaceae characterized by flowers with small petals and numerous prominent stamens...
and others) in a semi-arid region, after heavy precipitation. The species is known only from the type locality in Vale do Catimbau National Park
Vale do Catimbau National Park
The Vale do Catimbau National Park is a national park of Brazil, located in the city of Buíque in the state of Pernambuco. The Catimbau Valley or Vale do Catimbau in Portuguese is Brazil's 2nd largest archaeological site. Among its natural attractions there are beautiful canyons, over 2,000 caves,...
in Brazil, in the state of Pernambuco
Pernambuco
Pernambuco is a state of Brazil, located in the Northeast region of the country. To the north are the states of Paraíba and Ceará, to the west is Piauí, to the south are Alagoas and Bahia, and to the east is the Atlantic Ocean. There are about of beaches, some of the most beautiful in the...
. It fruits at an elevation of 900 to 1000 m (2,952.8 to 3,280.8 ft). This is part of the biodiverse cerrado
Cerrado
The Cerrado, is a vast tropical savanna ecoregion of Brazil, particularly in the states of Gioas and Minas Gerais...
ecoregion, in an area known as the campos rupestres
Campos Rupestres montane savanna
The Campos Rupestres montane savanna is a montane subtropical savanna ecoregion of eastern Brazil, a part of the cerrado ecoregion.-Setting:The ecoregion lies between 700 and 2000 meters elevation, forming several discontinuous enclaves in the Serra do Espinhaço, Serra da Mantiqueira, Serra dos...
. Although the fungus is suspected to be mycorrhiza
Mycorrhiza
A mycorrhiza is a symbiotic association between a fungus and the roots of a vascular plant....
l (like all Lactarius
Lactarius
Lactarius is a genus of mushroom-producing fungi. The genus, collectively known commonly as milk-caps, are characterized by the fact that they exude a milky fluid if cut or damaged...
), there was a wide diversity of plant species growing in the open, dry forest where the mushroom was found (including members of the tree families Euphorbiaceae
Euphorbiaceae
Euphorbiaceae, the Spurge family are a large family of flowering plants with 300 genera and around 7,500 species. Most are herbs, but some, especially in the tropics, are also shrubs or trees. Some are succulent and resemble cacti....
, Fabaceae
Fabaceae
The Fabaceae or Leguminosae, commonly known as the legume, pea, or bean family, is a large and economically important family of flowering plants. The group is the third largest land plant family, behind only the Orchidaceae and Asteraceae, with 730 genera and over 19,400 species...
, Myrtaceae
Myrtaceae
The Myrtaceae or Myrtle family are a family of dicotyledon plants, placed within the order Myrtales. Myrtle, clove, guava, feijoa, allspice, and eucalyptus belong here. All species are woody, with essential oils, and flower parts in multiples of four or five...
, Nyctaginaceae
Nyctaginaceae
Nyctaginaceae, the Four O'Clock Family, is a family of around 33 genera and 290 species of flowering plants, widely distributed in tropical and subtropical regions, with a few representatives in temperate regions...
, and Polygonaceae
Polygonaceae
Polygonaceae is a family of flowering plants known informally as the "knotweed family" or "smartweed family"— "buckwheat family" in the United States. The name is based on the genus Polygonum and was first used by Antoine Laurent de Jussieu in 1789 in his book, Genera Plantarum. The name refers...
—all known to form mycorrhizal associations), so the authors did not speculate on any specific interactions.