The spore print is the powdery deposit obtained by allowing spores of a fungal fruit body to fall onto a surface underneath. It is an important diagnostic character in most handbooks for identifying mushrooms. It shows the colour of the mushroom spores if viewed en masse. [1]
A spore print is made by placing the spore-producing surface flat on a sheet of dark and white paper or on a sheet of clear, stiff plastic, which facilitates moving the spore print to a darker or lighter surface for improved contrast; for example, it is easier to determine whether the spore print is pure white or, rather, very slightly pigmented. The mushroom is left for several hours, often overnight, in this manner. Some guides advise using a moisture-resistant enclosure, like a glass or jar, to contain the mushroom during printing. If the mushroom is to be preserved, a small hole can be made in the spore print paper rather than cutting the stipe. [2] When the mushroom is removed, the colour of the spores should be visible. Mycologists often use glass slides, which allow for quick examination of spores under a microscope. A mushroom cannot be identified from its spore print alone; the spore print is only one characteristic used in making a taxonomic determination. Spore prints are usually white to cream, black, or shades of red, purple, or brown. The poisonous false parasol (Chlorophyllum molybdites) has a green spore deposit. [3] Although the spore print is generally used to help identify the genus of a specimen, on occasion it can be used to help distinguish between similar species. For example, the lookalikes Russula crustosa and Russula virescens have yellowish and white spore deposits, respectively. [4]
In the field, spore print colour can sometimes be quickly determined by examining the top of stipes for spore "dust" on the nearby forest floor.[ clarification needed ] [5]
Collecting and examination of a spore print is not always successful. Some mushrooms are too young or too old to produce spores. Mushrooms collected at high elevations will typically not produce a spore print at lower elevations. [2] Sometimes, the colour can vary depending on the thickness of the spore print. In the genus Lactarius , for example, thin deposits are usually white, while thick deposits are cream to yellow. Many of the original authors of species guides in this genus did not indicate whether spore print colours they recorded were with thick or thin prints, limiting the usefulness of this feature as an identification characteristic. [6] In some instances, the colour of the spore print matches that of the mature gills, but this is not always true and gill colour cannot reliably be used as an indicator of spore print colour. [4]
The North American Mycological Association (NAMA) created a 'how-to guide' for people interested in creating their own spore prints. [7]
Historically the classification of many families of fungi were based on spore colour, a feature first systematically emphasized by Swedish mycologist Elias Fries. [8] An example is the Tricholomataceae, a large family containing many fungi whose common factor was having white spores. However recent molecular research has shown some strange relationships, with some fungi of disparate spore colours showing close relations.[ citation needed ]
The Russulaceae are a diverse family of fungi in the order Russulales, with roughly 1,900 known species and a worldwide distribution. They comprise the brittlegills and the milk-caps, well-known mushroom-forming fungi that include some edible species. These gilled mushrooms are characterised by the brittle flesh of their fruitbodies.
Russula is a very large genus composed of around 750 worldwide species of ectomycorrhizal mushrooms. They are typically common, fairly large, and brightly colored – making them one of the most recognizable genera among mycologists and mushroom collectors. Their distinguishing characteristics include usually brightly coloured caps, a white to dark yellow spore print, brittle, attached gills, an absence of latex, and absence of partial veil or volva tissue on the stem. Microscopically, the genus is characterised by the amyloid ornamented spores and flesh (trama) composed of spherocysts. Members of the related genus Lactarius have similar characteristics but emit a milky latex when their gills are broken. The genus was described by Christian Hendrik Persoon in 1796.
Lactarius torminosus, commonly known as the woolly milkcap or the bearded milkcap, is a large agaric fungus. A common and widely distributed species, it is found in North Africa, northern Asia, Europe, and North America. It was first described scientifically by Jacob Christian Schäffer in 1774 as an Agaricus, and later transferred to the genus Lactarius in 1821 by Samuel Frederick Gray. A variety, L. torminosus var. nordmanensis, is known from the United States, Canada, and Switzerland. L. torminosus officially became the type species of Lactarius in 2011 after molecular studies prompted the taxonomic reshuffling of species between several Russulaceae genera.
Lactifluus piperatus, commonly known as the blancaccio, is a semi-edible basidiomycete fungus of the genus Lactifluus. Despite being edible, it is not recommended by some because of its poor taste, though can be used as seasoning when dried. The fruiting body is a creamy-white mushroom which is funnel-shaped when mature, with exceptionally crowded gills. It bleeds a whitish peppery-tasting milk when cut. Widely distributed across Europe and eastern North America, Lactifluus piperatus has been accidentally introduced to Australia. Mycorrhizal, it forms a symbiotic relationship with various species of deciduous tree, including beech, and hazel, and fruiting bodies are found on the forest floor in deciduous woodland.
Russula delica is a mushroom that goes by the common name of milk-white brittlegill, and is a member of the genus Russula, all of which are collectively known as brittlegills. It is mostly white, with ochraceous or brownish cap markings, and a short robust stem. It is edible, but poor in taste, and grows in coniferous, broadleaved, or mixed woods. It can be confused with other white Russula species and certain white Lactarius species.
Lactifluus volemus, formerly known as Lactarius volemus, is a species of fungus in the family Russulaceae. It is widely distributed in the northern hemisphere, in temperate regions of Europe, North America and Asia as well as some subtropical and tropical regions of Central America and Asia. A mycorrhizal fungus, its fruit bodies grow on the ground at the base of various species of trees from summer to autumn, either individually or in groups. It is valued as an edible mushroom, and is sold in markets in Asia. Several other Lactifluus mushrooms resemble L. volemus, such as the closely related edible species L. corrugis, but these can be distinguished by differences in distribution, visible morphology, and microscopic characteristics. L. volemus produces a white spore print and has roughly spherical spores about 7–8 micrometres in diameter.
Lactarius vietus is a species of fungus in the family Russulaceae, first described by Elias Magnus Fries. It produces moderately sized and brittle mushrooms, which grow on the forest floor or on rotting wood. The flattened-convex cap can vary in shape, sometimes forming the shape of a wide funnel. It is typically grey, but the colour varies. The species has crowded, light-coloured gills, which produce white milk. The spore print is typically whitish, but also varies considerably. The mushrooms typically have a strong, acrid taste and have been described as inedible, but other authors have described them as consumable after boiling. L. vietus feeds by forming an ectomycorrhizal relationship with surrounding trees, and it favours birch. It grows in autumn months and is fairly common in Europe, North America and eastern Asia.
Lactarius subflammeus, commonly known as the orange milk cap, is a species of fungus in the family Russulaceae. It is found in western North America in the late summer and fall and is especially common in the Pacific Northwest, where it grows on the ground near conifers like pine and spruce. The brightly colored fruit bodies, which are slimy or sticky, have scarlet caps when young that soon fade to brilliant orange. The stem—typically longer than the width of the cap—is also bright orange but the gills are whitish. The mushroom secretes a whitish latex when it is cut or injured.
Lactarius aspideoides, commonly known as the bright yellow milkcap, is a species of fungus in the family Russulaceae. Distinctive characteristics of the fruit body include the sticky, pale yellow cap, and the abundant latex that stains the mushroom tissue lilac. It is found in North America.
Lactarius alnicola, commonly known as the golden milkcap, is a species of fungus in the family Russulaceae. The fruit bodies produced by the fungus are characterized by a sticky, vanilla-colored cap up to 20 cm (7.9 in) wide with a mixture of yellow tones arranged in faint concentric bands. The stem is up to 5 cm (2.0 in) long and has yellow-brown spots. When it is cut or injured, the mushroom oozes a white latex, which has an intensely peppery taste. The acrid taste of the fruit bodies renders them unpalatable. The fungus is found in the western United States and Mexico, where it grows in mycorrhizal associations with various coniferous trees species, such as spruce, pine and fir, and deciduous species such as oak and alder. It has also been collected in India. Two varieties have been named: var. pitkinensis, known from Colorado, and var. pungens, from Michigan.
Lactarius affinis, commonly known as the kindred milk cap, is a species of milk-cap mushroom in the family Russulaceae. It is found northeastern North America, where it fruits in the summer and fall, and is common in the Great Lakes region. Its fruit bodies have medium to large, slimy dull yellow or brownish caps. Although not considered poisonous, it is unpalatable because of its highly acrid taste.
Lactifluus deceptivus, commonly known as the deceiving milkcap, is a common species of fungus in the family Russulaceae. It is found throughout eastern North America on the ground in coniferous forests near hemlock or deciduous forests near oak, and in oak-dominated forests of Costa Rica. It produces large mushrooms with funnel-shaped caps reaching up to 25 cm (9.8 in) in diameter, on top of hard white stems that may reach 4–10 cm (1.6–3.9 in) long and up to 3 cm (1.2 in) thick. The gills are closely spaced together and yellowish-cream in color. When young, the cap is white in all parts, but the depressed center becomes dull brownish in age and breaks up into scales. The edge of the cap has a roll of cottony tissue that collapses as the cap expands. The surface of the stem—especially near the base—has a velvety texture. The mushroom "bleeds" a milky white acrid latex when it is cut or injured. Similar milk-cap species with which L. deceptivus might be confused include Lactifluus piperatus, L. pseudodeceptivus, L. caeruleitinctus, L. subvellereus, Lactarius arcuatus and Lactarius parvulus.
Lactarius rufulus, commonly known as the rufous candy cap, is a species of fungus in the family Russulaceae. The fruit bodies have fleshy brownish-red caps up to 10 cm (3.9 in) wide, and closely spaced pinkish-yellow gills. The stem is up to 12 cm (4.7 in) long and 3 cm (1.2 in) thick and colored similarly to the cap. The species, known only from California, Arizona, and Mexico, grows on the ground in leaf litter near oak trees. The fruit bodies resembles those of L. rufus, but L. rufulus tends to grow in clusters at a common base, rather than solitarily or in groups. A distinguishing microscopic characteristic is the near absence of large, spherical cells called sphaerocysts that are otherwise common in Lactarius species. Lactarius rufulus mushrooms are edible, and have an odor resembling maple syrup. They have been used to flavor confections and desserts.
Lactarius vinaceorufescens, commonly known as the yellow-staining milkcap or the yellow-latex milky, is a poisonous species of fungus in the family Russulaceae. It produces mushrooms with pinkish-cinnamon caps up to 12 cm (4.7 in) wide held by pinkish-white stems up to 7 cm (2.8 in) long. The closely spaced whitish to pinkish buff gills develop wine-red spots in age. When it is cut or injured, the mushroom oozes a white latex that rapidly turns bright sulfur-yellow. The species, common and widely distributed in North America, grows in the ground in association with conifer trees. There are several other Lactarius species that bear resemblance to L. vinaceorufescens, but most can be distinguished by differences in staining reactions, macroscopic characteristics, or habitat.
Asterophora parasitica, commonly known as the parasitic Asterophora or the Russula parasite, is a species of fungus that grows as a parasite on other mushrooms. The fruit bodies are small, with silky fibers on the surface of grayish caps and thick, widely spaced gills. Mushrooms fruit in clusters on the decaying remains of Lactarius and Russula species, particularly those in the Russula nigricans group. Found primarily in temperate zones of Europe and North America, the fungus is widespread but not common.
Hygrophorus purpurascens, commonly known as the veiled purple hygrophorus, is a species of agaric fungus in the family Hygrophoraceae. Its cap has a pink background color with streaks of purplish red overlaid, and mature gills have red spots.
Harrya chromapes, commonly known as the yellowfoot bolete or the chrome-footed bolete, is a species of bolete fungus in the family Boletaceae. The bolete is found in eastern North America, Costa Rica, and eastern Asia, where it grows on the ground, in a mycorrhizal association with deciduous and coniferous trees. Fruit bodies have smooth, rose-pink caps that are initially convex before flattening out. The pores on the cap undersurface are white, aging to a pale pink as the spores mature. The thick stipe has fine pink or reddish dots (scabers), and is white to pinkish but with a bright yellow base. The mushrooms are edible but are popular with insects, and so they are often infested with maggots.
Russula crustosa, commonly known as the crusty russula, is a species of fungus in the family Russulaceae. It is found in Asia and North America.
Hygrophorus russula, commonly known as the pinkmottle woodwax, false russula and russula-like waxy cap, is a fungus native to North America and Europe.