Major Groups > Boletes > Suillus

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The Genus Suillus  

[ Basidiomycetes > Boletales > Suillaceae . . . ]

by Michael Kuo

The distinctive features highlight reel for this genus of boletes includes the following:

  • Growth under conifers
  • Slimy caps
  • Glandular dots on the stem
  • Large pore openings that are often arranged radially
  • A partial veil that leaves a ring or tissue hanging from the cap margin

    The problem is, few of the Suillus mushrooms know they are supposed to manifest all of these features at once. This makes some of them a little difficult to identify to genus--but once one gets a feel for what is "Suillusy," it is a fairly easy genus to identify in the field. As a general rule of thumb, I usually expect any potential Suillus to demonstrate at least three of the features above. Alternatively, if you have a microscope, the presence of bundled, dark brown to blackish cystidia in the tubes (see the illustration) is in itself a reliable indicator of the genus Suillus.

    There are some very beautiful and impressive Suillus species--and, after fall rains, they can come up in stunning numbers. The genus Suillus is fascinating from a scientific perspective. Given the seemingly tentative way that Suillus is defined as a genus (usually more or less as I have done at the top of this page, with a checklist of characters that are not all demonstrated in all specimens), it is surprising how well the generic concept has held up over the years. The separate genus Fuscoboletinus, consisting mostly of Suillus-like mushrooms growing under larch or tamarack, did not fare as well, and was folded into Suillus (Bruns & Palmer, 1989; Kretzer et al., 1996).

    Before DNA studies, theorizing about the evolution of Suillus relied mostly on the idea that the boletes evolved from gastromycetes. The frequently elongated, radial (and sometimes nearly gill-like) pores of many Suillus species tempted theorists to place the genus between gilled mushrooms and boletes in a transitional zone, often with Phylloporus, the so-called "gilled boletes," nearby. However, such theories were the result of what I elsewhere call simple "pattern recognition," rather than true evolutionary theorizing, and DNA studies have demonstrated that actual phylogenetic relationships cannot be so easily inferred from the physical appearance of mushrooms.

    While the boletes have not received as much attention from molecular biologists as the gilled mushrooms, current DNA evidence places some puffballs and gilled mushrooms with the boletes. Suillus, it appears, is probably closely related to Chroogomphus and Gomphidius, among other genera. A 1996 study by Kretzer et al. found that most clades within Suillus (amended to include Fuscoboletinus) lined up neatly with the mycorrhizal host trees of the mushrooms, suggesting that ecology is a crucial determiner in the genus. In fact, specimens of Suillus granulatus collected under different hosts were revealed to be genetically distinct!

  •  

    Suillus granulatus

    Suillus sp.

    Suillus granulatus

    Suillus americanus

    Suillus salmonicolor

    Suillus sp.



    Key to 60+ Suillus Species in North America

    Bypass Links:

    Hardwoods
    Conifers, cap dry
    Conifers, cap viscid, glandular dots absent
    Conifers, cap viscid, glandular dots present, partial veil
    Conifers, cap viscid, glandular dots present, no partial veil


    1.Growing under hardwoods.
    2

    1.Growing under conifers.
    7


     [Hardwoods . . . ]
     

    2.Growing under oaks in the Great Lakes region; with a yellowish partial veil that extends nearly to the ground when the mushroom is young; flesh and pore surface bruising strongly brown; spores round or nearly so.

    2.Not as above.
    3


    3.Cap lacking conspicuous fibers or tufts of tissue; pores not radially arranged; stem without glandular dots.

    3.Cap with fibers or tufts of tissue; pore surface radially arranged or not; stem with or without glandular dots.
    4


    4.Tubes very shallow (only 2-3 mm deep); stem base purplish red.
    Suillus flavoluteus

    4.Not as above.
    5


    5.Pore surface radially arranged.
    6

    5.Pore surface not radially arranged.
    Suillus hirtellus
    at UM Herbarium


    6.Pore surface yellowish orange when young; stem with glandular dots by maturity; flesh olive with iron salts.

    6.Pore surface pinkish brown to buff when young; stem without glandular dots; flesh negative with iron salts.
    Suillus castanellus


    7.Fresh cap surface dry under normal conditions.
    8

    7.Fresh cap surface slimy or sticky under normal conditions. (In dry conditions, a once-slimy Suillus may have a glossy, shiny appearance--or have debris and needles stuck tightly to the cap.)
    18


     [Conifers; cap dry . . . ]
     

    8.Tubes grayish; cap with radially arranged, brownish to purplish fibers; stem usually with a fragile ring; known only from Maine; rare.
    Suillus solidipes

    8.Not as above.
    9


    9.Pore surface bruising blue; cut flesh bluing slowly and erratically; mushroom usually staining fingers brown on handling; several color forms documented.

    9.Pore surface not bruising blue (but may bruise brown); cut flesh bluing or not.
    10


    10.Growing under larch, tamarack, or Douglas-fir.
    11

    10.Growing under pines (species of Pinus).
    15


    11.Growing under Douglas-fir; cap reddish; stem base typically solid.

    11.Growing under larch or tamarack; cap variously colored; stem base solid or not.
    12


    12.Cap dark brown; stem base with a hollow cavity.

    12.Cap otherwise colored; stem base typically solid.
    13


    13.Cap pallid (buff to pale olive or grayish); pink and red shades absent.
    Suillus grisellus
    at UM Herbarium

    13.Cap more highly colored; pink or red shades present.
    14


    14.Found in western North America; taste usually somewhat acrid or bitter; partial veil sometimes leaving a ring on the stem or fragments on the cap margin.
    Suillus ochraceoroseus
    at UM Herbarium

    14.Found east of the Rocky Mountains; taste mild; partial veil rarely leaving a ring on the stem or fragments on the cap margin.
    Suillus paluster
    at UM Herbarium


    15.Found in western North America; young cap densely hairy/scaly with olive to brownish fibers.
    Suillus fuscotomentosus
    at MykoWeb
    = S. acerbus

    15.Found east of the Rocky Mountains; young cap not as above.
    16


    16.Ring or ring zone absent.

    16.Ring or ring zone present, at least some of the time.
    17


    17.Found from New Jersey to Florida and Texas; fresh, young cap orangish, pinkish, dull yellow, or pale brownish; partial veil disappearing by maturity or leaving only a ring zone.

    17.Found from the Carolinas to eastern Canada and Minnesota; young, fresh cap dark rose to red; partial veil often forming a fairly sturdy (though usually collapsed) ring on the stem.


    18.Stem without glandular dots (check mature specimens).
    19

    18.Stem with glandular dots, at least at maturity.
    46


     [Conifers; cap viscid; glandular dots absent . . . ]
     

    19.Growing under larch or tamarack.
    20

    19.Growing under other conifers.
    24


    20.Sliced flesh turning greenish or bluish (sometimes slowly and weakly).
    21

    20.Sliced flesh not turning greenish or bluish.
    22


    21.Sliced flesh turning purplish gray after initial bluish stage, eventually turning reddish brown; fresh cap covered with thick, brown slime over a whitish base color; northeastern in distribution.
    Suillus serotinus
    at UM Herbarium
    see also photo

    21.Sliced flesh not turning other colors after initial bluish stage; cap with thick, colorless slime over a grayish to brownish (sometimes yellowish) base color; widely distributed in northern North America, reported from Mississippi with introduced trees.
    Suillus laricinus
    at UM Herbarium
    = S. aeruginascens


    22.Cap pallid (buff to pale olive or grayish); red shades absent.
    Suillus grisellus
    at UM Herbarium

    22.Cap more highly colored; red shades present.
    23


    23.Cap surface with pinkish to reddish brown tufts or scales; spore print purple-brown; pore surface usually bruising pinkish; spores 9-15 x 4-6.5 µ.
    Suillus spectabilis
    at UM Herbarium

    23.Cap surface without tufts or scales, reddish brown to brown; spore print dull cinnamon; pore surface bruising brownish; spores 8-10 x 2.5-4.5 µ.
    Suillus grevillei
    at Fungi of Poland


    24.Growing under Douglas-fir.
    25

    24.Growing under other conifers.
    26


    25.Cap surface thickly slimy when fresh; partial veil coated with slime; ring with a slimy underside; flesh in cap not usually changing when sliced; flesh in stem base not blue green when sliced.

    25.Cap surface sticky to thinly slimy when fresh; partial veil dry; ring dry; flesh in cap sometimes turning pinkish when sliced; flesh in stem base blue green when sliced.


    26.Growing under Redwood and Tanbark Oak.

    26.Growing under other conifers.
    27


    27.Growing under true firs (Abies), spruce, or hemlock.
    28

    27.Growing under pines.
    30


    28.Stem without a ring; cap dirty yellow. (Note: Poorly documented species.)
    Suillus appendiculatus

    28.Stem with a ring; cap otherwise colored.
    29


    29.Cap smooth, dull orange to cinnamon brown (often with greenish shades mixed in); spore print dull cinnamon; flesh in stem base sometimes blue green when sliced.
    Suillus imitatus
    at Boletes of CA

    29.Cap smooth or with pressed-down fibers, dark rusty brown to dark brown when fresh; spore print dark brown to purple-brown; flesh in stem base sometimes reddish when sliced.
    Suillus sinuspaulianus
    at UM Herbarium


    30.Partial veil leaving a ring or ring zone on the stem.
    31

    30.Partial veil absent--or present but leaving no remnants on the stem.
    33


    31.Pore surface radially arranged and boletinoid; stem with red colorations.
    Suillus sinuspaulianus
    at UM Herbarium

    31.Pore surface not radially arranged, not boletinoid; stem without red colorations.
    32


    32.Partial veil typically sheathing the lower stem at maturity; flesh unchanging when sliced; recorded under various pines in western North America.
    Suillus pseudobrevipes
    at Boletes of CA

    32.Partial veil ephemeral and leaving, at most, a fragile ring zone on the stem; flesh usually turning pinkish when sliced; perhaps exclusive to western white pine.
    Suillus albivelatus


    33.Found east of the Rocky Mountains.
    34

    33.Found in western North America.
    37


    34.Found only under Scots pine; flesh becoming pinkish or orangish when sliced (sometimes bluing in older mushrooms).
    Suillus bovinus
    at Fungi of Poland

    34.Found under various pines; flesh not changing when sliced.
    35


    35.Stem often short in proportion to cap; cap dark brown or purplish brown, fading to cinnamon; pore surface initially whitish, becoming yellow, not bruising; cap surface dark brown or black with ammonia.

    35.Not completely as above.
    36


    36.Found under various pines, often in sandy soil; margin with a thick cottony roll of tissue (a "false veil"); pore surface initially whitish, later yellowish, not bruising; spore print yellowish brown; flesh pink, then slowly gray with ammonia.

    36.Probably exclusive to Eastern White Pine; margin lacking a false veil; pore surface yellowish from the first, bruising brownish; spore print cinnamon brown; flesh red with ammonia.
    Suillus lactifluus
    = S. granulatus


    37.Partial veil present, covering pore surface in button-stage mushrooms and leaving remnants on the cap margin when the mushroom is still young.
    38

    37.Partial veil absent in all stages of development (though one species has a false veil, in which white marginal tissue is present on the cap but does not reach the stem).
    39


    38.Flesh turning pinkish when sliced; cap surface not streaked; pore surface initially whitish, later yellowish.
    Suillus albevilatus

    38.Flesh unchanging when sliced; cap surface often streaked; pore surface yellowish from the first.
    Suillus borealis
    at Boletes of CA


    39.Pore surface running down the stem distinctively, extending a centimeter or more down the apex; known from California under Ponderosa Pine.
    Suillus anomalus

    39.Not as above.
    40


    40.Pore surface strongly boletinoid to nearly gill-like; known from Idaho and Oregon.
    Suillus helenae

    40.Not as above.
    41


    41.Flesh staining blue when sliced; pore surface bruising blue; stem reticulate; growing under Lodgepole Pine; known from Devil's Postpile National Monument in California.
    Suillus reticulatus
    at Boletes of CA

    41.Not as above.
    42


    42.Cap with tiny fibers when young, light brown to cinnamon brown; stem swollen in the middle, with a bulbous base; pore surface bright yellow when young; growing under Lodgepole Pine; known from El Dorado and Nevada counties in California.
    Suillus monticolus
    at Boletes of CA

    42.Not as above.
    43


    43.Cap brown to dark brown when young, fading somewhat with age to cinnamon brown; stem often short in proportion to cap; cap surface dark brown to black with ammonia.

    43.Cap paler at first; stem not usually short in proportion to cap; ammonia reaction of cap surface pinkish or red (not recorded in one case, but this species apparently exclusive to Lodgepole Pine).
    44


    44.Cap margin with a wide or narrow extension of overhanging tissue, at least when young.
    45

    44.Cap margin even, without overhanging tissue; known only from Arizona, under Ponderosa Pine.
    Suillus occidentalis


    45.Known only from Idaho, under Lodgepole Pine; stem not discoloring brown near the base or developing brown shades; mushroom staining waxed paper brown; chemical reactions not recorded.
    Suillus pallidiceps

    45.Known from the Pacific Coast and possibly Colorado, under various pines and possibly fir or spruce; stem discoloring brown near the base and often developing brown glandular dots in age; effect on waxed paper not recorded; cap surface and flesh pink, then gray with ammonia.


    46.Partial veil present, covering the pore surface of mushrooms in the button stage, later remaining as tissue fragments on the cap margin, and/or as a ring or ring zone on the stem.
    47

    46.Partial veil absent.
    73


     [Conifers; cap viscid; glandular dots present; partial veil present...]
     

    47.Found east of the Rocky Mountains.
    48

    47.Found in western North America.
    60


    48.Pore surface bruising (brownish, reddish, cinnamon brown, etc.; sometimes slowly).
    49

    48.Pore surface not bruising.
    54


    49.Partial veil dry and cottony or Kleenex-like (under normal conditions), leaving an evanescent and fragile ring--or merely a ring zone--on the stem.
    50

    49.Partial veil slimy, leaving a fairly sturdy ring which is often collapsed and/or gelatinous.
    52


    50.Cap initially whitish or buff, becoming yellowish with age; flesh whitish; taste of cap slime (sorry) very acidic; growing under Red Pine.
    Suillus acidus
    at UM Herbarium

    50.Cap yellowish from the beginning; flesh yellowish; taste of slime mild or faintly acidic; growing under pines or tamarack.
    51


    51.Mature stem often crooked or twisted, typically not more than 1 cm wide; cap fairly bright yellow when not faded, with reddish patches or streaks; exclusive to eastern white pine.

    51.Mature stem not typically crooked, usually more than 1 cm wide; cap dull yellow, with reddish, pressed-down scales; growing under western white pine or limber pine.


    52.Taste of cap slime (sorry) acidic.

    52.Taste of cap slime mild or faintly acidic.
    53


    53.Mature cap often broadly bell-shaped (with a central bump), usually yellowish; pore surface radially arranged; cap surface purplish red with ammonia.
    Suillus flavidus
    = Suillus umbonatus ?

    53.Mature cap more or less flat or broadly convex (without a central bump), pinkish buff to cinnamon or tan; pore surface not radially arranged; cap surface negative with ammonia.
    Suillus subalutaceus
    at UM Herbarium


    54.Stem without a ring or ring zone.
    55

    54.Stem with a ring.
    56


    55.Cap often pale at first, later yellowish to cinnamon, tan, or brown; "partial veil" only a false veil, not touching the stem when mushroom is in the button stage, remaining as a roll of tissue on the cap margin; glandular dots inconspicuous at first.

    55.Cap yellowish at first, becoming tan or cinnamon; partial veil true, covering pore surface when in the button stage, leaving a roll of tissue on the cap margin; glandular dots conspicuous throughout development.
    Suillus glandulosipes
    at Boletes of CA


    56.Stem bruising yellow when handled, especially near the base.
    Suillus lutescens
    at UM Herbarium

    56.Stem not bruising yellow.
    57


    57.Young cap dark brown to dark reddish brown; partial veil and ring usually with lilac to purple shades.

    57.Young cap paler than above (yellowish, tan, cinnamon brown, etc.); partial veil and ring without lilac or purple shades.
    58


    58.Taste of slime on cap surface (sorry) strongly acidic; cap pale yellow when young, darkening with age; cap surface brown with KOH.

    58.Taste of slime mild; cap sometimes pale yellow when young, but typically more tan or brown; cap surface reaction to KOH not brown.
    59


    59.Partial to Jack Pine in northern and northeastern North America; partial veil and ring with a thick, whitish roll of tissue on the bottom.
    Suillus salmonicolor
    = S. subluteus

    59.Partial to Loblolly Pine and Longleaf Pine in the southeast; partial veil and ring lacking a thick, whitish roll of tissue on the bottom.
    Suillus corthunatus


    60.Partial veil consistently producing a fairly durable ring on the stem, or forming a prominent sheath around the lower stem (examination of multiple specimens may be required). We're talking rings with machismo here.
    61

    60.Partial veil not leaving remnants on the stem, or consistently producing a ring zone, but not a true ring or sheath. In short: ring absent or wimpy.
    64


    61.Pore surface bruising pale cinnamon; glandular dots pale at first, darkening in age or on handling; stem usually 1 cm wide or less; cap olive or yellowish when young, becoming cinnamon to tan; flesh pale yellow, turning pale cinnamon when sliced; cap surface purplish red with ammonia.
    Suillus flavidus
    = Suillus umbonatus ?

    61.Not completely as above.
    62


    62.Young cap dark brown to dark reddish brown; partial veil and ring usually with lilac to purple shades.

    62.Young cap typically paler than above; partial veil and ring without lilac to purple shades.
    63


    63.Stem often short in proportion to cap, up to 3 cm thick at apex; cap yellowish, yellowish brown or reddish brown; partial veil sheathing the lower stem and leaving a thin ring or ring zone; glandular dots whitish.
    Suillus pseudobrevipes
    at Boletes of CA

    63.Stem not short in proportion to cap, up to 2 cm thick at apex; cap olive brown or tan; partial veil sheathing the lower stem and leaving an olive brown ring with a thick lower edge; glandular dots pinkish brown, darkening to blackish in age or on handling.
    Suillus subolivaceus
    at Boletes of CA


    64.Pores very large (to 5 mm x 3 mm), radially arranged and nearly gill-like; stem frequently disproportionately small, and often not central; cap tan with brownish to cinnamon brown scales or hairs; ammonia grayish lavender on the cap surface, red on the tubes; known from the Sierra Nevada.
    Suillus megaporinus
    at Boletes of CA

    64.Not completely as above.
    65


    65.Mature stem slender (not wider than 1.5 cm); mature cap yellow or yellowish, with reddish or cinnamon patches, scales or hairs.
    66

    65.Mature stem wider than above; cap not as above.
    67


    66.Often found under western white pine; pore surface bruising cinnamon; cap sometimes broadly bell-shaped, yellowish from the first.

    66.Often found under Ponderosa Pine and Sugar Pine, near dead logs and stumps; pore surface not bruising; cap convex to planoconvex, at first brownish with a yellow margin.
    Suillus riparius
    at Boletes of CA


    67.Cap white at first, covered with slime that darkens to dark brown or purplish brown; stem base bruising purplish brown to brown; partial veil white when covering the pore surface; glandular dots inconspicuous until maturity.
    Suillus brunnescens
    at Boletes of CA

    67.Not completely as above.
    68


    68.Fruiting in summer months under Jeffrey Pine; known from Lassen Volcanic National Park in California; glandular dots inconspicuous until maturity; stem short and squat in proportion to cap, darkening with age; cap yellowish, with a roll of pale partial veil material on the margin when young.
    Suillus volcanalis
    at Boletes of CA

    68.Not completely as above.
    69


    69.Glandular dots conspicuous (dense, darker than the stem surface).
    70

    69.Glandular dots inconspicuous, at least when the mushroom is young.
    71


    70.Odor pungent; found under pines--especially Monterey Pine--from June to October.
    Suillus pungens
    at MykoWeb

    70.Odor not distinctive; found under various pines from September to January.
    Suillus glandulosipes
    at Boletes of CA


    71.Partial veil purplish to reddish brown when covering pore surface; found under conifers, especially western white pine, in the Pacific Northwest and the Rocky Mountains; cap surface often streaked.
    Suillus borealis
    at Boletes of CA

    71.Partial veil not purplish to reddish brown; found under various conifers; cap surface not typically streaked.
    72


    72.Partial veil a false veil--appearing as a roll of tissue on the cap margin, but not touching the stem or completely covering the pore surface when in the button stage; flesh not changing when sliced; cap surface smooth or finely hairy.

    72.Partial veil a true veil, covering the young pore surface, later resulting in fragments on the cap margin and/or an ephemeral ring zone; flesh sometimes changing to pinkish when sliced; cap surface smooth.
    Suillus albivelatus


     [Conifers; cap viscid; glandular dots present; partial veil absent...]
     

    73.Found east of the Rocky Mountains.
    74

    73.Found in western North America.
    84


    74.Cut flesh staining blue.

    74.Cut flesh not staining blue
    75


    75.Cap and pore surface bright yellow throughout development.
    Suillus unicolor
    at UM Herbarium

    75.Cap and pore surface not bright yellow.
    76


    76.Young pore surface brown to dark brown.

    76.Young pore surface not brown.
    77


    77.Cap margin with a conspicuous roll of tissue (a "false veil").

    77.False veil absent.
    78


    78.Cap brown to dark brown.
    79

    78.Cap otherwise colored (whitish, yellowish, orangish, cinnamon).
    80


    79.Stem often short in proportion to cap; pore surface not boletinoid, not bruising; glandular dots not conspicuous; stem not bruising.

    79.Stem not short in proportion to cap; pore surface boletinoid, bruising brownish; glandular dots conspicuous; stem often bruising and discoloring brown.
    Suillus punctatipes
    at Boletes of CA


    80.Flesh staining pinkish or reddish when sliced.
    81

    80.Flesh not staining when sliced.
    82


    81.Cap white when young, eventually yellowish, smooth.
    Suillus placidus
    at UM Herbarium

    81.Cap orangish to yellowish, with scattered reddish or brownish pressed-down hairs.


    82.Pore surface whitish at first; cap usually with a mottled or mosaic appearance by maturity; stem white when young, sometimes becoming yellowish.

    82.Pore surface yellowish from the beginning; cap not mottled at maturity; stem yellowish from the first.
    83


    83.Cap yellowish, with reddish to brownish tufts of hairs; glandular dots yellowish at first, darkening in age; found under various conifers.
    Suillus hirtellus
    at UM Herbarium

    83.Cap buff when young, cinnamon in age, smooth; glandular dots inconspicuous and not darkening with age; apparently exclusive to Eastern White Pine.
    Suillus lactifluus
    = S. granulatus


    84.Sliced flesh staining blue.
    85

    84.Sliced flesh not staining blue.
    86


    85.Pore surface dingy yellowish; cap without yellow shades; stem discoloring brownish when handled.
    Suillus tomentosus var. discolor

    85.Pore surface brownish; cap yellowish to yellow-brown; stem not discoloring when handled.


    86.Glandular dots inconspicuous.
    87

    86.Glandular dots conspicuous, at least by maturity.
    91


    87.Pore surface boletinoid.
    Suillus helenae

    87.Pore surface not boletinoid.
    88


    88.Cap with tiny fibers when young, light brown to cinnamon brown; stem swollen in the middle, with a bulbous base; pore surface bright yellow when young; growing under Lodgepole Pine; known from El Dorado and Nevada counties in California.
    Suillus monticolus
    at Boletes of CA

    88.Not as above.
    89


    89.Known only from Grand Teton National Park, Wyoming, under Western White Pine; cap brown to purplish brown over a white base color; stem white with brown glandular dots and a yellowish apex at maturity; spore print olive to olive brown.
    Suillus subalpinus

    89.Not as above.
    90


    90.Stem often short in proportion to cap; found under pines; flesh not staining when sliced; stem base bruising pinkish, then brownish; cap blackish with ammonia.

    90.Stem not typically short in proportion to cap; found under Ponderosa Pine and other conifers; flesh sometimes staining pinkish when sliced; stem base not bruising; cap reaction to ammonia not recorded.
    Suillus albivelatus


    91.Cap white when young, later yellowish; flesh slowly staining pinkish when sliced; glandular dots at first pinkish, later brown; cap pink, then red or blackish with ammonia; found in eastern North America under Eastern White Pine but reported from Washington under 5-needle pine.
    Suillus placidus
    at UM Herbarium

    91.Not as above.
    92


    92.Cap margin with a conspicuous roll of tissue (a "false veil").

    92.False veil absent.
    93


    93.Found primarily under Monterey Pine; odor strong and pungent; cap color very variable (pale at first, becoming orangish, yellowish, or cinnamon); pore surface white at first, later yellowish; glandular dots reddish to brown.
    Suillus pungens
    at MykoWeb

    93.Not as above.
    94


    94.Pore surface whitish at first; cap usually with a mottled or mosaic appearance by maturity; stem white when young, sometimes becoming yellowish; pore surface often bruising dull cinnamon; cap bluish gray with ammonia.

    94.Not as above.
    95


    95.Found under Ponderosa Pine in the Southwest.
    96

    95.Found under various pines in California and the Pacific Northwest.
    97


    96.Pore surface at first with reddish glandular dots; flesh pale yellow; odor pungent; stem base without dark red stains.
    Suillus wasatchicus

    96.Pore surface without glandular dots; flesh white; odor not distinctive; stem base often with dark red stains.


    97.Pore surface yellow from the first.
    98

    97.Pore surface white at first, later developing yellow shades.
    99


    98.Cap smooth throughout development, pale to dirty yellowish brown; pores large and angular (1-2.5 mm across); spore print cinnamon brown.
    Suillus flavogranulatus

    98.Cap conspicuously hairy or scaly with brown fibers when young, base color pale yellowish; pores small (1-2 per mm); spore print olive brown.
    Suillus fuscotomentosus
    at MykoWeb
    = S. acerbus


    99.Pore surface boletinoid, sometimes bruising brownish; cap margin not inrolled when young, lacking a white band of tissue.
    Suillus punctatipes
    at Boletes of CA

    99.Pore surface not boletinoid, not bruising; cap margin inrolled when young, with a white band of tissue.
    Suillus glandulosipes
    at Boletes of CA


    Excluded Species

    Suillus appendiculatus:   Originally described as Boletinus appendiculatus by Peck in 1896, and placed in Suillus by Smith & Thiers (1964). Apparently known only from the type collection, which "consists of one badly battered specimen" (Both, 1993, p. 27). The specimen was sent by the collector to Peck, probably from the state of Washington--but Singer (1945) created confusion by listing the collection location as Washington, D. C. This is not the same species as Boletus apppendiculatus Schaeffer: Fries.

    Suillus californicus:   Named by Murrill as Rostkovites californicus in 1915, and apparently known only from the type collection (Grass Valley, California, 1914). The collector's description was brief, and the type consists of half a mushroom.

    Suillus ruber:   Described from dried specimens by Singer & Sipe (1948) as a bright red species with bluing flesh in western North America. Smith & Thiers (1964, p. 57) suspect it is a color variant of Suillus tomentosus.




    (References used for this page can be found in the reference list for boletes.)



    Cite this page as:

    Kuo, M. (2004, November). The genus Suillus. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/suillus.html


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