This section is from the book "Our Edible Toadstools and Mushrooms and How to Distinguish Them", by W. Hamilton Gibson. Also available from Amazon: Our Edible Toadstools And Mushrooms And How To Distinguish Them.
Among the toadstools which tradition would surely brand as poisonous on account of "bright color" is the common species whose name heads this paragraph, and which is illustrated in Plate 22, fig. 2. In its various shapes it suggests the preceding varieties. Its cap, however, is brownish red, often bright brick red. Flesh almost lemon-yellow, stained red just beneath the cuticle, and not noticeably changeable on fracture. Tube surface yellowish green, turning blue or bluish green when bruised. Spores light brown. Tubes rather large, angular, and unequal in shape of aperture. Stem yellow, often brightly colored with the red of the cap. Chance cracks in its surface become red, whence the common name of the "Red-cracked Boletus." A species frequent in woods throughout the summer and autumn, and edible.
In its brightly colored cap it might possibly be superficially confounded with the suspicious Boletus alveolatus of Plate 24. But the latter species is easily distinguished by its rose-colored spores and red pore surface.
Pileus: Diameter two to four inches; convex, becoming more flattened; soft to the touch, varying from light yellowish brown to bright brick red; more or less fissured with red cracks and clincks.
Flesh: Rich, bright yellow, red immediately beneath the cuticle.
Tube surface: Olive-yellow, becoming bluish where bruised; tube openings rather large, angled, and unequal in size.
Stem: Generally stout and straight; yellowish, and more or less streaked or spotted with the color of the cap.
Spores: Light brown.
Habitat: Woods and copses.
Season: Summer and autumn.
Plate XXII Boletus Subtomentosus. Boletus chrysenteron.