Boletus porosporus G. Moreno & Bon syn. Xerocomus porosporus (G. Moreno & Bon) Contu Cap up to 8cm across; dark olive-brown then sepia to cigar-brown; at first with yellow down that darkens on bruising, later cracking to show yellowish flesh, particularly at centre. Stem 90–100×20–30mm; apex lemon-chrome, sometimes with brown to blood-red zone, slightly ribbed with olivaceous-brown, darkening when bruised. Flesh pale lemon-yellow to buff in cap, stem apex lemon-chrome, base dark brick or vinaceous, finally becoming blue after cutting, particularly above the tubes; taste and smell not distinctive. Tubes lemon-yellow, finally olivaceous, bruising blue. Pores compound, angular; lemon-yellow, darkening with age, bruising blue. Spores 13–15×4.5–5.5¼, subfusiform, with distinct truncate pore (only visible on mature spores), making this species unique among European boletes. Spore print olivaceous walnut-brown. Habitat in mixed deciduous woods, particularly with oak; autumn. Occasional. Edible but not recommended.
