An analysis employing parsimony and character compatibility methods is carried out for selected species in the various families constituting the order Boletales s.l. (H°iland 1987). The results indicate that Paxillaceae is paraphyletic, actually representing a primitive matrix from which many of the other families have evolved. Gyrodontaceae is polyphyletic, and its various genera should be included within other families. The analysis does not support that Xerocomaceae and Boletaceae should be regarded as two separate families. It indicates that the genus Suillus should be included within Gomphidiaceae, leaving Suillus variegatus in an isolated position more close to members in Boletaceae. On the other hand, it strongly contradicts any relationship between Suillus and Chalciporus on one hand, and Strobilomyces on the other. The latter genus must be very isolated from the other genera analysed. The gastroid families Rhizopogonaceae and Chamonixiaceae seem to have derived from progenitors related to Suillus (Bruns et al. 1989) and Gyroporus (here regarded within Paxillaceae) respectively. Coniophoraceae (with Coniophora and Serpula) is probably derived from precursors related to the more primitive representatives in Paxillaceae. The fully gastroid Sclerodermatacea (with Pisolithus, Scleroderma, and Astraeus), probably belong within Boletales (Gill & Watling 1986), perhaps remotely connected to the clade giving rise to Strobilomycetaceae (Fischer 1995).


                      ====== Pisolithus
          =Sc=========|
          |           |  === Scleroderma
          |           ===|
    ======|              === Astraeus
    |     |     
    |     =St=============== Strobilomyces
    |
    |     ================== Paxillus atrotomentosus
    |     |
    |     |     ============ Paxillus panuoides
    |  ===|  ===|
    |  |  |  |  |  ========= Serpula
    |  |  |  |  =C=|
    |  |  ===|     ========= Coniophora
    |  |     |
    |  |     |         ===== Hygrophoropsis
    |  |     ==========|
    |  |               ===== Omphalotus
    |  |        
    =P=|           ========= Paxillus involutus
       |           |
       |  =========|  ====== Gyrodon                             
       |  |        |  |
       |  |        ===|
       |  |           |  === Gyroporus
       |  |           ===|
       |  |              =X= Chamonixia
       |  |                  
       |  |              === Suillus bovinus
       |  |        ======|
       ===|        |     =R= Rhizopogon
          |        |
          |  =G====|     === Chroogomphus
          |  |     |  ===|
          |  |     |  |  === Gomphidius
          |  |     ===|
          |  |        |  === Suillus luteus
          |  |        ===|
          |  |           === Suillus grevillei
          ===|
             |  ============ Boletinus
             |  |
             |  |       ==== Xerocomus
             |  |  =====|
             =B=|  |    ==== Phylloporus
                |  |
                |  |======== Chalciporus
                ===|
                   |======== Leccinum
                   |
                   |  ====== Boletus
                   ===|
                      |  === Pulveroboletus
                      ===|
                         === Suillus variegatus
                

St = Strobilomycetaceae
Sc = Sclerodermataceae
P = Paxillaceae (paraphyletic)
C = Coniophoraceae
X = Chamonixiaceae
G = Gomphidiaceae (including Suillaceae) (paraphyletic)
R = Rhizopogonaceae
B = Boletaceae (including Xerocomaceae)

Bruns, T.D., Fogel, R., White, T.J. & Palmer, J.D. 1989. Accelerated evolution of a false-truffle from a mushroom ancestor. - Nature (Lond.) 339: 140-142.

Fischer, M. 1995. Zur Systematik der Boletales: Isolierung und Kennzeichnung von DNA aus Fruchtk÷rpern und Mycelkulturen. - Z. Mykol. 61: 245-260.

Gill, M. & Watling, R. 1986. The Relationships of Pisolithus (Sclerodermataceae) to other Fleshy Fungi with Particular Reference to the Occurrence and Taxonomic Significance of Hydroxylated Pulvinic Acids. - Plant Syst. Evol. 154: 225-236.

H°iland, K. 1987. A new approach to the phylogeny of the order Boletales (Basidiomycotina). - Nord. J. Bot. 7: 705-718.