Order Hymenomycetes. Tribe Pileati. 



Plate XXII. 



BOLETUS PACHYPUS, 5..^ 



Oeii. Cliar. Hymenium distinct from the substance of the pUeus, consisting of cylindric separable tubes. 

 Spores oblong. Name from /SiXor, a hall ; from the rounded form of many of them. 



Spec. Char. B. pachypus. " Pileus six to seven inches broad, dry, puli'inate, subtomentose, pale reddish 

 brown, very thick and fleshy, when young firm, when full-grown very soft ; flesh white, uot changeable. Tubes free, 

 at first lemon-coloured, afterwards dirty yellow, simple. Stem three to four inches high, two inches and a half thick, 

 bulbous, often swollen from the top, rarely equal, reticulated, yellowish when young, sub-rufescent when old. Some- 

 times two or three specimens spring from the same root." "The tubes do not become blue when touched." 

 " Another form, with the tubes at first bright yellow, the stem extremely thick and not in the least reticulated, but 

 rough like that of B. scaber, and neither flesh nor tubes changeable, occurred in May at King's Cliffe, Norths. 

 Spores pale olivaceous ochre. Taste and smell like that of A. Georgii (the Horse-mushroom); the yellow expressed 

 juice distinctly acid. 

 Boletus pachypus, Berkeley, Fties^ 



Hah. Under trees on a hedge-bank, Wj-mondham, Norfolk, June. 



The large varieties of Boletus have a similar rude hastily developed irregular growth, often compressed 

 and distorted from meeting with obstacles to their swelhng out equally in every part of the pileus ; specimens 

 of B. eduU-s, B. 2^achijpus, B. scaber, kc, may be so aberrant from theii' true nature, as at first sight to be 

 taken for each other. The attempt to fix on positive specimens of each species to give the student correct 

 ideas of them is so far difficult, that the defimtions of our present authorities, are not very ample or strict, 

 nor accordant with each other ; and tliis is not sm-prising since ill-grown, or over-gromi, or diseased Boletuses 

 are constantly presenting themselves, which it is an exercise of botanical acumen to refer to their proper 

 place ; the patience and mgenuity of tlie student will find ample scope in classing a basket of mixed Boletuses 

 produced as they often are in large quantities, after heavy summer-rain, partaking of every form and colour, 

 and varying not more fi-om their kindred, than from themselves, according as they are affected by soil and 

 situation, by temperature and weather. The changing colour when broken may certainly be depended upon 

 in determuiing any Boletus, so far as the intensity of the blue or any other shade acquired by the exposure 

 of the juices to the air, may vary according to the moist or dry state of the flesh, or its age, but a changeable 

 Eungus is changeable always, and does not turn blue at one time and not at another; if therefore any Boletus 

 is cited as tumiug blue, and another as not doing so, they may be near relatives, but Jiot the same although 

 their outward resemblance should be considerable. An unerring test is the colour of the spores, which may 

 be collected by placing the pileus on a glass, the spores of a given individual being always of the same hue. 

 Some of the Boletus tribe when their tubes are longitudinally divided, are found to have them quite simple, 

 others have compound tubes, wliich means that at some distance from their attachment to the pileus, they 



