Fungi Key – Suillus

This is a trial key for Queensland Suillus. QMS would greatly appreciate your feedback: info [at] qldfungi.org.au

Is it a Suillus?

The genus Suillus has a very specific host range, they only grow with conifers and in Queensland they only grow with introduced Pines in forest plantations or in parks and gardens. They are in the Bolete group so all have pores on the lower surface of the cap. The cap surface of this group of fungi is usually viscid, sometimes very slimy.

If you look at the stipe with a lens you will observe small dots which are glands. If your fungus has a viscid cap, pores, glands on the stipe and it is growing under a Pine tree, then it is a Suillus. Five species have been recorded in Queensland: S. bovinus, S. corthunatus, S. granulatus, S. luteus and S. salmonicolor. But S. bovinus is doubtful and has only been recorded once and S. corthunatus is thought to be an earlier name for S. salmonicolor.
 
Notes on Using this Key
This key requires you to determine the following characters for your specimen:

Cap: colour and size;
Stipe: presence of ring and glands;
Flesh: colour change;
Pores: colour, shape;
Habitat: host tree.
 

Key

1.	Stem with a ring or ring zone	2
1.*	Stem lacking a ring	3
2.	Cap grey brown, very viscid, flesh pale yellow or white, with Scots Pine (Pinus sylvestris) or Monterey Pine (P. radiata)	Suillus luteus
2.*	Cap pale yellow to pale brownish, flesh orange and under Slash Pine (Pinus elliottii) or Caribbean Pine (P. caribaea and its hybrids). See notes on S. cothurnatus	Suillus salmonicolor
3.	Stipe without noticeable punctae (dots) or with very few; cap cinnamon, pores large, under Scots Pine (Pinus sylvestris)	Suillus bovinus
3.*	Stipe with clearly defined punctae; cap yellowish brown and growing with Scots Pine (Pinus sylvestris) or other European pines	Suillus granulatus

 
 

Species Descriptions

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Suillus bovinus (Pers.) Roussel

Common name:	Jersey Cow Bolete
Cap:	convex to broadly convex, 35–80 mm diam.; viscid at first but soon drying; cinnamon to clay pink, with a distinctly paler margin.
Stipe:	cylindrical; 40–60 × 5–8 mm; concolourous with cap; ring absent, not punctate or barely so, mycelium pink.
Pores:	ochraceous; quite large (1 or 2 per mm) and angular.
Flesh:	white or slightly yellow, slowly turning clay pink on exposure to air.
Spores:	subfusoid; 8–10 × 3–4 µm.
Habitat:	mostly recorded with Scots Pine (Pinus sylvestris) but also occurs with North American pines.
Records:	only a single record in Queensland.
Notes:	Recognised by its pale cinnamon colour, lack of a ring, angular pores and its association with Scots Pine.

 

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Suillus cothurnatus Singer

Cap:	convex becoming applanate; 16 – 60 mm diameter; smooth, viscid; orange, dirty yellow or pale brown.
Stipe:	cylindrical; 25–60 × 5–10 mm; with a white gelatinous ring and reddish brown punctae on a yellowish background.
Pores:	yellow to orange, fading to brown; angular; 1–2 per mm.
Flesh:	yellow to orange, darker in stem base, not changing on exposure to air, staining brown with KOH.
Spores:	subfusoid; 7–10 × 2.5–3.5 µm.
Habitat:	mycorrhizal with Loblolly Pine (Pinus taeda)
Records:	one record from urban Brisbane, Qld, Australia (Watling & Li 1999). The identity of the host is not recorded nor any field characters.
Notes:	There seems to be some disagreement in the American literature on the critical differences between S. cothurnatus and S. salmonicolor. The Queensland record appears to pre-date the publication of S. salmonicolor, and thus needs to be re-examined before the presence of S. cothurnatus in Australia can be accepted, especially since recent collections have all been of S. salmonicolor. Suillus cothurnatus is not included in the key.

 

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Suillus granulatus (L.) Roussel

Common name:	Weeping Bolete
Cap:	convex at first, becoming applanate; 30–90 mm diameter; viscid at first becoming shiny when dry; rusty to yellowish brown, becoming paler as it dries.
Stipe:	tapering slightly towards the base; 35–80 × 7–12 mm; ring absent; creamy yellow and covered in yellow punctae that exude the milky drops that gives the fungus its common name.
Pores:	buff to pale yellow, unchanging.
Flesh:	lemon yellow to lemon chrome in the stipe, paler in the cap.
Spores:	subfusiform; 8.4–11.7 × 2.7–4.2 µm.
Habitat:	grows in troops with the Scots Pine, Pinus sylvestris and other European 2-needle pines.
Records:	six records in Queensland.
Notes:	Distinguished from S. subacerbus by its association with Scots Pine and the negative reaction to a drop of KOH on the cap.

 

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Suillus luteus (L.) Roussel

Common name:	Slippery Jack
Cap:	convex; 50–120 mm diam.; very viscid but becoming dry and shiny eventually; purplish chestnut to cigar brown, sometimes with olivaceous or sepia tints.
Stipe:	cylindrical or slightly clavate; 50–100 × 20–30 mm; with a large pale glutinous ring; glandular dots above and below ring; yellow above the ring and straw coloured below at first but becoming a vinaceous brown.
Pores:	lemon yellow to straw colour; small (2-3 per mm) and round.
Flesh:	white overall, but pale lemon near top of cap and vinaceous brown at base.
Spores:	subfusiform; 7–9.5 × 2.5–3.7 µm.
Habitat:	usually found with Scots Pine or other two-needle European and North American pines.
Records:	found in southern parts of the state and on the Darling Downs but only one collection in the Queensland Herbarium.
Notes:	Easily recognised by its large membranous ring, cap colour, vinaceous brown glandular dots and association with two-needle pines.

 

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Suillus salmonicolor (Frost) Halling

Common name:	Slippery Jill
Cap:	convex becoming applanate; 30–100 mm diam.; smooth, viscid; orange, dirty yellow or pale brown.
Stipe:	cylindrical; 30–100 × 8–15 mm; with a white gelatinous ring and often with a conspicuously thickened cottony roll on the base; reddish brown punctae on a yellowish background.
Pores:	yellow to orange, fading to brown; angular; 1–2 per mm.
Flesh:	yellow to orange, darker in stem base, not changing on exposure to air, purplish red with KOH.
Spores:	subfusoid; 7–10 × 2.5–4 µm.
Habitat:	mycorrhizal with Slash Pine (Pinus elliottii) Caribbean Pine (P. caribaea) and Jack Pine (P. banksiana).
Records:	a single collection from Qld, in a Caribbean Pine plantation (BRI, MEL). Newly reported herein.
Notes:	The Australian collection consists of small fruiting bodies, which have remarkably orange flesh. The host is believed to be an F1 hybrid of Caribbean and Slash Pines. See notes under S. cothurnatus, which is separated by the reaction to KOH on the flesh and microscopical differences in the structure of the punctae.

 

Pat Leonard
2012