Type: Mycorrhizal Fungi; Description: Basidiomata pileate. Pileus dull reddish brown to chocolate brown, 60–120 mm in diameter, convex to plano-convex, mucilaginous; flesh white. Pore surface adnate to subdecurrent; tubes pale yellow at first becoming deep ochre yellow, 5–10 mm long; pores at first concolorous with the tubes becoming spotted dark reddish brown, angular, 0.5–1.0 mm in diameter. Stipe more or less cylindrical, pale yellow above a conspicuous white annulus, brownish below, with numerous reddish brown glandulae, 40–90 mm long. Basidiospores elliptical, 0-septate, 7–9 × 2–3 μm, smooth, pale yellow.

Distribution: Northland, Auckland, Coromandel, Waikato, Bay of Plenty, Taupo, Wanganui, Wellington, Nelson, Buller, Westland, Marlborough Sounds, North Canterbury, Mid Canterbury, South Canterbury, Dunedin, Southland, Chatham Islands.; 1st Record: Birch (1937: as Boletus luteus).

Significance: Isolated from and experimentally shown to be a mycorrhizal partner of Pinus radiata (Chu-Chou 1979).; Host(s): Pinus banksiana, P. contorta, P. lambertiana, P. muricata, P. nigra subsp. laricio, P. patula, P. ponderosa, P. radiata.

COLLECTIONS EXAMINED: Under (1) Pinus banksiana, Canterbury, Ashley Forest, Feb 1965, R. M. J. Mackenzie, 24679; (2) P. contorta, Eyrewell Forest, Feb 1965, R.M.J.M., 24311; (3) P. lambertiana, Eyrewell Forest, Mar 1965, R.M.J.M., 24683; (4) P. muricata, Eyrewell Forest, Mar 1965, R.M.J.M., 24682; (5) P. patula, Auckland. Kauaeranga State Forest, Mar 1965, R.F.R. McN., 24680; (6) P. pinaster, Canterbury, Chaneys, Feb 1965, R.M.J.M., 24681; (7) P. ponderosa, Burke's Pass, Feb 1965, R.M.J.M., 24313; (8) P. radiata, Auckland, Riverhead State Forest, Jul 1964, R.F.R. McN., 23623; Blockhouse Bay, Mar 1965, R.F.R. McN., 24685; Kauaeranga State Forest, Mar 1965, R.F.R. McN., 24687; Orakeikorako, Apr 1965, R.F.R. McN., 24684; Mamaku, Apr 1965, R.F.R. McN., 24689; Marlborough, Rarangi Bay, Apr 1965, W. A. Holloway, 24688; Nelson, Rabbit Island, W.A.H., 24686.

PILEUS: convex to plano-convex, 6-12 cm diam., mucilaginous, glabrous, sometimes faintly and innately radiately fibrillose, typically dull reddish brown or chocolate brown, occasionally golden brown, tawny, or with greyish or purplish overtones imparted by the thick mucilage layer; cuticle an ixotrichodermium, readily separable; margin often lacerate. HYMENOPHORE: tubes 5-10 mm long, adnate to sub-decurrent, whitish to pallid yellow when young, becoming deep ochre yellow at maturity; pores at first concolorous with tubes, becoming spotted dark reddish brown, irregularly angular, 0.5-(l) mm diam. STIPE: 4-9 cm long, more or less equal, 1-2.5 cm diam., solid, pallid yellow above annulus, brownish below; glandulae numerous apically, yellow to reddish brown, fewer and more scattered basally; flesh white to pallid yellow: annulus conspicuous, occasionally disintegrating with age, superior, broadly sheathing, upper surface sordid white, lower surface with purplish tints. SPORES: spore print yellowish brown, (Clay Color); spores pallid melleous, elliptic-subfusiform, 7.4-9-(10) X 2.5-3.2 µm, smooth. HYMENIUM: basidia hyaline, clavate, 14-26 X 4.5-7.5 µm, 4-spored; cystidia often crowded in groups, hyaline or encrusted with brown, resinous material, cylindrical to clavate, occasionally lageniform, 25-65 X 6-12 µm. HYMENOPHORAL TRAMA: bilateral, of the Boletus subtype; clamp connections absent. CONTEXT OF PILEUS: white to pallid yellow, unchanging on exposure to air. TASTE: mild. SMELL: not distinctive. CHEMICAL REACTIONS: KOH on pileus—dark grey; on context of pileus—immediate red flush turning lilac; NH4OH on pileus—dark grey; on context—immediate red flush turning deep lilac to purplish.

HABITAT: Gregarious or occasionally caespitose under Pinus.

ILLUSTRATIONS: Kallenbach, Die Pilze Mitteleuropas 1 (8): pl. 19. 1928; Smith and Thiers, A Contribution Toward a Monograph of North American Species of Suillus pl. 23. 1964.

Pileus 10-23 cm, diam., glutinous, dark brown drying lighter brown, pellicle peeling, flesh soft, yellow. Pores 5-10 mm, long X 0.5-1 mm, diam., yellow, becoming olive brown with age, usually adnate, occasionally slightly decurrent. Stipe 1.5-2.5 X 5-8 cm., with a well developed membranous ring, yellow with more or less conspicuous glandulae above, light brown below, Spores 9-10 X 3.5um.

commonly associated throughout the country with Pinus radiata, though more abundant in the South than in the North, its distribution being somewhat complementary to that of Amanita muscaria which is also associated with this tree.

The New Zealand form of this fungus appears to be usually more robust, and with more strongly developed yellow colour than the common European forms as illustrated by Bresadola (1931) and Kallenbach (1940).