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Go to the NZFungi website for more indepth information on Xerocomus macrobbii. Xerocomus macrobbii

Synonyms

Boletus macrobbii

Biostatus

Present in region - Indigenous. Endemic

Images (click to enlarge)

 

Caption: FIG. 1. X. mcrobbii: h, spores; i. cystidia.
Caption: Fig. 8 - b, Xerocomus mcrobbii (x1)
Caption: ZT8683
Owner: E. Horak: © Creative Commons Attribution-Noncommercial 3.0 New Zealand
 

Article: McNabb, R.F.R. (1968). The Boletaceae of New Zealand. New Zealand Journal of Botany 6(2): 137-176 (http://www.rsnz.org/publish/abstracts.php).
Description: PILEUS: convex, 2-4.5 cm diam., dry, finely felted to subtomentose when young, becoming coarsely fibrillose-scaly at maturity, olive at first, cuticle rupturing at maturity to form adpressed scales and exposing the yellowish brown or reddish context beneath; cuticle a disorganised cutis; scales composed of septate hyphae 4-7 µm. diam., with brownish contents; margin entire to slightly crenulate-lacerate. extending beyond pores. HYMENOPHORE: tubes 6-10 mm long. deeply excavated around apex of stipe, yellow; pores dark red, concolorous with apex of stipe, angular, 0.5-(l) mm diam. STIPE: 3.5-5.5 cm long. more or less equal, 0.5-1 cm diam., solid, dry, with adpressed squamules often arranged in irregular rings around stipe, dark red apically, yellow basally; flesh and basal mycelium bright yellow, annulus absent. SPORES: spore print not obtained; spores deep melleous, broadly elliptical to elliptic-subfusiform, occasionally obovate. 9.7-14.3 X 4.5-7.2 µm, smooth. HYMENIUM: basidia hyaline, clavate, 32-49 X 9.8-14 µm, 4-spored; cystidia sparse, scattered, hyaline, thin-walled, subcylindrical to narrowly ventricose-rostrate, 45-63x4-7 µm. HYMENOPHORAL TRAMA: bilateral, of the Phylloporus subtype; clamp connections absent. CONTEXT OF PILEUS: bright yellow, unchanging on exposure to air. TASTE AND SMELL: not distinctive.
Habitat: HABITAT: Gregarious or occasionally caespitose under Nothofagus.
Notes: Xerocomus mcrobbii has the general appearance of a Boletellus, but may be distinguished from members of that genus by the short smooth spores and hymenophoral trama of the Phylloporus subtype. Although the ammonia reaction of fresh pilei is not known, the short spores (Q=2) indicate that Xerocomus mcrobbii most probably belongs in sect. Pseudogyrodontes. The fact that it has been found only under Nothofagus in two widely separated localities suggests that it is a mycorrhizal species.
Xerocomus mcrobbii may be recognised by the olive pileus, which becomes fibrillose-scaly at maturity, yellow tubes and deep red pores, and short spores.