Arora, D. (2008). California Porcini: Three new taxa, observations on their harvest, and the tragedy of no commons. Economic Botany 62: 356-375.Boletus rex-veris D. Arora & Simonini sp. nov.
Pileus rufus, testaceus vel suffusus ochraceus, vulgo siccus. Pagina pori juventute alba, lutescens tum olivacens vel viridulescens. Stipes crassus, juventute albus sed maturitate saepe bruneus vel ferrugineus suffusus, ad partem superam reticulatus. Contextus crassus, albus, ubi incisus immutabilis. Sporae 15â€“ 17Ã—4.5â€“4.9 Î¼m. Pileipellis trichodermium inter- textum. Typus hic designatus Arora 2254 (SFSU), Pilgrim Creek Rd., McCloud, CA.Etymology: (rex, king; veris, of the spring)
Pileus (cap) 10â€“30 cm broad or occasionally larger, broadly convex or bun-shaped, becoming nearly plane or uneven, usually reddish-brown but varying to tan or paler where hidden by soil or humus and often developing ochre tones in age or where exposed to sunlight, and at other times dark dull brown. Surface typically not viscid except when wet or old, glabrous except for a very fine white bloom that covers often irregular areas of the young cap. Pore surface and tube layer white when young, gradually becoming yellow or yellowish-buff and finally olive-yellow or greenish; pores near the pileus margin may become cinnamon-brown in areas, but the pore surface doesnâ€™t become uniformly brown or cinnamon. Stipe 2.5â€“10 cm thick and 5â€“20 cm long or more, typically clavate with a pointed (and often curved) base when young, becoming more or less equal in age but usually retaining a tapered or pointed base. Stipe surface white when young, often developing tan or more often reddish-brown tinges in age, especially in the upper portion but occasionally throughout; typ- ically reticulate over the upper portion; reticulum fine and white when young (and sometimes barely discernible), often brown in age as the meshes become wider and coarser. Context white in both the cap and the stipe (or reddish-tinged just above the tube layer), unchanging when cut, firm; odor and taste mild.
Spores olive-brown in deposit but yellowish under the microscope, ellipsoid-subfusiform with a prominent suprahilar depression, (14) 15â€“17 (19)Ã—(4) 4.5â€“5 (5.2) Î¼m, Q=(3.02) 3.25â€“3.65 (3.87), n = 31. Basidia (40) 45â€“60 (65) Ã— 9â€“ 11.5 Î¼m, clavate, 4-spored. Pleurocystidia cylindrical-fusiform, hyaline, (45) 50â€“65 Ã— 6.5â€“ 7.5 Î¼m. Cheilocystidia clavate, sometimes narrowing or with capitulum or wide-fusiform, (30) 45â€“ 70 Ã— 11â€“17 Î¼m. Pileipellis an interwoven trichodermium, often weakly gelatinized in old speci- mens but typically not at all gelatinized in young ones, made up of chains of cells with cylindrical end cells having sharpened or rounded tips, (20) 30â€“80 (128) Ã— (6.5) 8â€“14 (20) Î¼m.