* Pore surface yellow when young but soon becoming red, then orange red. (1/2)
* Not as above. (2/2)
Stem yellow above, pink to reddish below; cap surface green, then olive with ammonia; flesh bright yellow, then gray with ammonia. (1/7)
Boletus pallidoroseus
Stem yellow above, rosy red or darker red below; cap surface yellowish or red, then olive with ammonia; flesh yellowish (greenish blue near tubes) with ammonia. (2/7)
Boletus peckii
Stem golden yellow above, pale yellow but dotted or streaked burgundy red below; cap surface yellowish with ammonia; flesh dark yellow with ammonia. (3/7)
Boletus rufomaculatus
Stem yellowish or brownish but without red shades; cap surface showing a green flash, then reddish brown with ammonia; flesh reaction with ammonia unknown. (4/7)
Xerocomus ferrugineus
Stem rusty cinnamon to brown; cap surface "bluish green, then bright orange surrounded by dull grayish green, then entirely yellow orange" (Bessette, 2000) with ammonia; flesh negative with ammonia. (5/7)
Boletus subcaerulescens
Stem mostly yellow, with reddish brown streaks; cap surface instantly reddish brown with ammonia; flesh reaction with ammonia unknown. (6/7)
Xerocomus subtomentosus
Stem whitish to yellowish, often with reddish areas or a reddish zone; cap pink with ammonia; widely distributed east of the Rockies. (7/7)
Butyriboletus brunneus