Key to 60+ Marasmioid Mushrooms in North America
|1.||Decomposing debris of plants (grasses, sedges, rushes, ferns, flowers, vines, etc.).|
|1.||Decomposing tree litter.|
|2.||Growing in grassy areas, in troops or fairy rings; cap 1–5 cm across and usually broadly bell-shaped, buff to tan; gills well spaced.|
|2.||Cap much smaller (rarely over 15 mm across); growing in grassy areas or not.|
|3.||On litter of salal and Oregon grape; odor of garlic; Pacific Northwest.|
|3.||Substrate different; odor not distinctive; variously distributed.|
|4.||On litter of mountain avens or on living avens; arctic and alpine ecosystems.|
|4.||Substrate different; variously distributed.|
|5.||Fresh cap white, buff, or pale (perhaps with a slightly darker center); western species.|
|5.||Fresh cap more highly colored; eastern and western species.|
|6.||Mature cap to only 2 mm across, buff to pale fawn with a cinnamon center; spores 8–12 x 4–6 µm.|
|7.||Cap pure white; spores 13–16 x 5–6.5 µm.|
|7.||Cap whitish with pinkish to cinnamon tinges over the center; spores 8–9 x 4 µm.|
|8.||Base of stem without prominent basal mycelium or fuzz; spores 7–11 x 3–5 µm.|
|8.||Base of stem with mycelium or fuzz; spores variously sized.|
|9.||Pennsylvania to Louisiana and Illinois; spores 13–19 x 3.5–5 µm.|
|9.||Widely distributed; spores 8.5–10.5 x 3.5–4 µm.|
|10.||On debris of conifers.|
|10.||On debris of hardwoods.|
|11.||Odor of garlic or onions, or strong and foul (crush a cap between your thumb and finger).|
|11.||Odor not distinctive.|
|12.||Odor strong and foul, but not of garlic or onions; on needles of spruce, fir, or pine (one or two mushrooms per needle); cap dull brown, beige, or nearly white.|
|12.||Odor distinctly of garlic or onions.|
|13.||Mature cap extremely tiny (under 3 mm across); whitish, dull pinkish, or brownish gray. I see no convincing way to separate these two species, with or without a microscope.|
|13.||Mature cap larger than above (4 to 20 mm across); more highly colored.|
|14.||Stem surface more or less velvety.|
|15.||Scattered or in loose troops on litter of pines (Pinus species); maximum cap size about 10 mm; stem base inserted directly into needles; spores 7.5–9 x 3–4 µm.|
|15.||In dense troops on litter of Douglas-fir, true firs (Abies species) or pines (Pinus species); maximum cap size about 20 mm; stem base not inserted directly; spores 9–10 x 5–6 µm.|
|16.||Fresh cap whitish to very pale grayish or faintly pinkish.|
|16.||Fresh cap more highly colored.|
|17.||Growing from needles; gills not developing pinkish stains; stem remaining fairly pale; spores 9–10 µm long.|
|17.||Growing from twigs or small logs; gills often developing pinkish stains; stem darkening from the base up with age; spores 12–19 µm long.|
|18.||Fresh cap rose, pink, red, wine colored, purple-red, etc.|
|18.||Fresh cap otherwise colored (orange, brown, orangish brown, cinnamon, rust, olive brown, yellow brown . . . ).|
|19.||Cap conspicuously pleated; rose pink, fading to pinkish with a darker center; growing on needles east of the Rocky Mountains.|
|19.||Cap not conspicuously pleated; more highly colored when fresh; growing on various substrates; western.|
|20.||Growing on well decayed wood; cap 5–20 mm across; gills often with a tiny tooth running down the stem; spores 8–13 x 3–4 µm.|
|20.||Growing on humus; cap 10–40 mm across; gills often nearly free; spores 11–15 x 5–6.5 µm.|
|21.||Cap conspicuously pleated; eastern species.|
|21.||Cap somewhat lined or not, but not conspicuously pleated; eastern and western species.|
|22.||Fresh cap orange to brownish orange; common from about Tennessee northward; spores 16–23 x 3–4 µm; odor not distinctive; taste mild to slightly bitter; large cystidia with refractive contents present.|
|22.||Fresh cap cinnamon or rusty brown; common from about Tennessee southward; spores 15–18 x 3–4.5 µm; odor and taste often mealy; cystidia absent or rare (if present, without refractive contents).|
|23.||Cap olive brown, fading to light yellowish brown, pale olive brown, or grayish brown (the center often darker than the margin); often growing with ferns nearby; stem with a long root that extends into the substrate; spores shaped like lemons.|
|23.||Cap without olive tones; root lacking; spores otherwise shaped.|
|24.||Growing on debris of redwoods on the West Coast; cap brown to brownish orange or orangish, 6-12 mm wide; taste (not odor) strongly garlic-like after 1–2 minutes.|
|24.||Not completely as above.|
|25.||Cap more or less "brown," without orange shades.|
|25.||Cap with orange to orange-brown shades, fading to dull apricot.|
|26.||Cap pale brownish or yellowish brown, with a darker brown center; gills without cystidia.|
|26.||Cap medium brown to dark brown; gill edges with upside-down mutant cow udders in miniature ("diverticulate" or "broom" cells) as cystidia.|
|27.||Growing from twigs or small logs; cap white, not pleated; stem darkening from the base up; gills often developing pinkish stains; spores 12–19 µm long.|
|27.||Not completely as above.|
|28.||Growing on debris of other hardwoods.|
|29.||Growing on petioles of sycamore leaves; cap minute, pale becoming pinkish brown.|
|30.||Growing on bark litter of madrone; cap to 1 cm across, brown; odor and taste of garlic or onions.|
|31.||Growing on litter of black locust; cap 4–13 mm across, pale orange (usually darker over the center and paler marginally), strongly or faintly pleated; recorded from Michigan but probably to be expected throughout the range of the tree.|
|32.||Growing on leaf litter of American holly; cap minute, pale with a darker brownish center.|
|33.||Gills attached by means of a collar that encircles the stem.|
|33.||Gills attached directly to the stem.|
|34.||Growing on debris of tanoak.|
|34.||Growing on debris of birch, quaking aspen, or black cottonwood.|
|35.||Odor of garlic or onions; cap 5–10 mm across, dark reddish brown.|
|35.||Odor not distinctive; other features variable.|
|36.||Cap to 6 mm across, dark brown fading to light brown.|
|37.||Cap tiny (5 mm across maximum) and whitish.|
|38.||Growing on leaves of birch or quaking aspen; spores 8–11 µm long; basidia 4-spored.|
|38.||Growing on leaves of black cottonwood (Populus trichocarpa); spores 11–14 µm long; basidia 2-spored.|
|39.||Odor of garlic or onions (crush a cap between your thumb and finger).|
|39.||Odor not distinctive, somewhat foul, spermatic, bleachlike, mealy, or radishlike—but not of garlic.|
|40.||Stem bald; most spores under 10 µm long; cheilocystidia digitate with many fingerlike projections.|
|40.||Stem hairy to finely velvety; most spores longer than 10 µm; cheilocystidia lumpy and lobed, with only a few, vaguely fingerlike projections.|
|41.||Found in western North America.|
|41.||Found east of the Rocky Mountains.|
|42.||Fresh cap rose pink, red, purplish red, or wine colored.|
|42.||Fresh cap otherwise colored.|
|43.||Found in western North America.|
|43.||Found east of the Rocky Mountains.|
|44.||Growing on well decayed wood; cap .5–2 cm across; gills often with a tiny tooth running down the stem; spores 8–13 x 3–4 µm.|
|44.||Growing on humus; cap 1–4 cm across; gills often nearly free; spores 11–15 x 5–6.5 µm.|
|45.||Cap purple red to red, perhaps fading to reddish brown.|
|46.||Gills pinkish, often with red edges; spores 16–22 x 4–5.5 µm.|
|46.||Gills whitish to yellowish, the edges colored like the faces; spores 8.5–12 x 3–4 µm.|
|47.||Mature cap regularly at least 2–3 cm across (often even larger); stem not wiry. (If cap is 2–3 cm across and the stem is not wiry, try this choice first.)|
|47.||Mature cap rarely as wide as 2–3 cm; stem wiry or not.|
|48.||Cap whitish with a dark brown or reddish brown center; found in eastern North America.|
|49.||Entire stem remaining pale (whitish to yellow or very pale brownish) throughout development.|
|49.||At least the lower portion of stem dark (brown, reddish brown, orange-brown, etc.) by maturity.|
|50.||Growing from leaf litter, twigs, or logs; cystidia present on gill faces and edges.|
|51.||Fresh cap pale (whitish, yellowish, pinkish cinnamon).|
|51.||Fresh cap some shade of brown.|
|52.||Mature cap whitish with a very slightly darker center, becoming somewhat wrinkled; gills with dextrinoid cystidia (setae).|
|52.||Mature cap pinkish cinnamon with a paler margin, not usually wrinkled; gills with colorless cystidia and broom cells.|
|53.||Often growing in clusters of 2–3 mushrooms; gills with dextrinoid cystidia (setae).|
|53.||Usually growing scattered to gregariously; gills with colorless to yellowish cystidia and broom cells.|
|54.||Fresh cap white or nearly so (pale yellowish, buff, cream).|
|54.||Fresh cap more highly colored.|
|55.||Cap conspicuously pleated.|
|55.||Cap smooth to wrinkled or faintly lined, but not conspicuously pleated.|
|56.||Usually growing on sticks, woody debris, and logs; cap at maturity with a flat top in side view.|
|56.||Usually growing on leaves; cap at maturity evenly rounded-convex in side view.|
|57.||Cap minute (2 mm maximum width); growing on leaves of American beech.|
|58.||Stem surface smooth or minutely pubescent.|
|58.||Stem surface finely to prominently hairy (use a hand lens on fresh specimens).|
|59.||Cap 2–13 mm across; usually growing on sedges, rushes, ferns (etc.) but also recorded on twigs of alder, willow, beech, tulip poplar, sycamore, pine, and hemlock; cystidia not dextrinoid.|
|59.||Cap 7–40 mm across; usually growing on twigs or leaves of oaks, but recorded on debris of other hardwoods; cystidia dextrinoid.|
|60.||Entire stem remaining whitish or pale brownish over the course of development.|
|60.||At least the bottom portion of the stem darkening to brown, dark brown, or black with maturity.|
|61.||Growing from hardwood leaves or leaf stems, or from grasses or vines; pileipellis a hymeniform layer of broom cells.|
|61.||Growing from hardwood sticks; pileipellis a cutis with lobed or slightly diverticulate terminal elements.|
|62.||Stem becoming brown to dark brown (if blackish, only at the base); spores ellipsoid to pip-shaped.|
|63.||Threadlike black rhizomorphs often found in the substrate (sticks); gills sometimes discoloring orangish with age; pileipellis with setae; spores 13–20 µm long.|
Marasmius tenerrius var. setulosis
|63.||Rhizomorphs absent; gills not discoloring orangish; pileipellis without setae; spores 8–13 µm long.|
|64.||Color of fresh cap ranging from orange to orange-brown to rusty or reddish brown.|
|64.||Color of fresh cap ranging from brown to light brown to yellow-brown to tan or olive brown.|
|65.||Mature cap conspicuously pleated or prominently lined.|
|65.||Mature cap smooth or faintly lined, but not conspicuously lined or pleated.|
|66.||Spores under 12 µm in length; cap initially brown to yellow-brown but sometimes fading to orangish brown; growing on leaves.|
|66.||Spores longer than 12 µm; cap with orange or rusty shades from the beginning; growing on leaves or woody debris.|
|67.||Cap 3–8 mm across; rare; documented from Tennessee.|
Marasmius haematocephalus var. anomaloides
|67.||Cap larger than above; common throughout eastern North America.|
|68.||Found in northeastern North America from roughly the 43rd parallel northwards; many spores under 15 µm in length; odor reminiscent of Pleurotus ostreatus.|
|68.||Found south of the 43rd parallel or perhaps above it; nearly all spores longer than 15 µm; odor not distinctive or mealy.|
|69.||Fresh cap orange to brownish orange; common from about Tennessee northward; spores 16–23 x 3–4 µm; odor not distinctive; taste mild to slightly bitter; large cystidia with refractive contents present.|
|69.||Fresh cap cinnamon or rusty brown; common from about Tennessee southward; spores 15–18 x 3–4.5 µm; odor and taste often mealy; cystidia absent or rare (if present, without refractive contents).|
|70.||Stem smooth or very finely hairy, usually not rooting; cap cuticle with broom cells.|
|71.||Found in northeastern North America from roughly the 43rd parallel northwards; spores over 12 µm in length; odor reminiscent of Pleurotus ostreatus.|
|71.||Widely distributed; spores shorter than 12 µm; odor not distinctive.|
|72.||Apparently limited to eastern North America; cap 6–25 mm across, bright orange or dark orange-brown when fresh; broom cells and cystidia present on gills.|
|72.||Apparently widely distributed in North America; cap 4–12 mm across, orange to orangish but rarely bright orange; broom cells present on gills but not cystidia.|
|73.||Basal half of stem remaining fairly pale through maturity.|
|73.||At least the basal half of the stem dark brown to black by maturity.|
|74.||Stem usually eccentric (sometimes central); stature minute (cap 1–7 mm across, stem under 3 mm long).|
|74.||Stem usually central (sometimes slightly erratic); small but not minute (cap 3–24 mm across, stem 26–40 mm long).|
|75.||Usually growing on curled, blackened ash leaves (but recorded on elm, poplar, and other hardwood leaves); cap minute (under 4 mm across), grayish brown to light brown.|
|75.||Not completely as above.|
|76.||Growing on leaves of oaks or tanoak in western North America; cap minute (2–5 mm across), light brown over the center and paler marginally.|
|76.||Not completely as above.|
|77.||Stem quite long (60–100 mm long), with a scurfy surface.|
|77.||Stem shorter than above (between 5 and 65 mm long), with a smooth to faintly hairy or pubescent surface.|
|78.||Spores under 12 µm long.|
|78.||Spores over 13 µm long.|
|79.||Cap conspicuously pleated at maturity; stem smooth; odor spermatic; spores 16–24 µm long.|
|79.||Cap wrinkled or somewhat lined along the margin at maturity, but not conspicuously pleated; stem faintly hairy or pubescent; odor not distinctive; spores 13.5–18 µm long.|
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Kuo, M. (2013, January). Marasmioid mushrooms. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/marasmioid.html