porcini mushrooms warning
Porcino is the common name for some species of fungi of the genus Boletus, often attributed, even as commodity name, four species of boletes (section Edules of the genus Boletus) headed to Boletus edulis and having morphological and organoleptic vaguely similar.
Some came to make mycologist twelve different species, discriminating depending on birth environments, trees budding, microscopic and macroscopic characters (shape, color and proportions of the fruiting body).
But the coded species from current and mycology that experts are able to recognize at first sight for their appearance clearly different, are four:
Boletus edulis, Sally: Fries
Popular names: brisa, bastard, stain fungus, moccicone, SAHNI
Boletus aereus, Sally: Fries
Popular names: bronzino, black fungus, MOP, moreccio, toilet brush, (Sardinia)
Boletus aestivalis (formerly reticulatus), (Paulet) Fries
Popular names: ceppatello, estatino, stataiolo, white mushroom, porcini in summer
Boletus pinophilus (formerly pinicola) Pilát & Dermek,
Popular names: red head, cold mushroom, pine mushrooms.
Edulis-Waxy, often wrinkled, wet weather (very) viscose (hence moccicone), exceeding the same hat with a thin clear margin. Color from bianchiccio to citrine to even very dark brown, almost black, sometimes with reddish tones. All'Abetone, in Tuscany, you know of fungaie which produce carpophores with greenish coloration (mushrooms Baker). 
Aereus veloute, Finely-ochre (= bronze coloured aereus) to black. Grey-black when ripe, without or with ocher fiammature.
Aestivalis-slightly velvety Hazel until dark brown. Ochre-Brown, also from young and wet weather. With dry weather tends to become color beige and divide into areoles that give a glimpse of the white flesh underneath.
Pinophilus-Rather damp, wrinkled when young. Garnet red colour or leather. In young age the edge of hat is sprinkled with fine whitish powder that can be combined with reddish hue, assume Fund blue-greenish.
Edulis -White And Immutable.With a Pink-Purple sheet more or less frequently under the cuticle.
Aereus -White And Immutable.
Aestivalis-White And Immutable.Sometimes pale yellow color in the layer in contact with the tubules. Easily attacked by insect larvae, especially in dry weather.
Bouquet: very intense.
Pinophilus -White And Immutable.reddish layer under the cuticle.
Odour: slightly sharp, distinctive.
Taste: sweet but that is the smell.
Boletus edulis-Ubiquitous. Typical of the forests of FIR and spruce, beech and in many areas of chestnut. To the North was born in pine and birch trees. With favorable season birth begins in mid-July and may continue until late November or until the appearance of the first cold.
Boletus aereus-Symbiont of deciduous forests of Mediterranean atmosphere, chestnut, oak, including Cedars, Oaks and cork trees, especially with undergrowth of broom. May appear in mid-June but is typical of late summer and autumn.
Boletus aestivalis-under broad-leaved trees (oak, chestnut, beech) and in favourable vintages under fir trees. Often the first specimens are found in mid May. The latest in early November, in Hill stations or plain hot zones of the South and out to sea.
Boletus pinophilus-under beech, chestnut and fir trees. The North also under par (hence the name). It prefers the undergrowth of Blueberry but does not disdain other environments (some areas of Pratomagno in Tuscany, they are rich while being completely absent the Blueberry). Makes his first appearance in late spring and in favourable conditions can arise in high altitudes throughout the summer until early November. (wikipedia article)
The information and images contained in this section are only for illustrative purpose, no exhortation or educational use and 'propio in peril it is always advisable for the identification of mushrooms to go with Local Health ____ PREVENTION DEPARTMENT SERVICE FOOD HYGIENE AND NUTRITION INSPECTOR mycological