Short descriptions and camera lucida drawings are given of cross-sections through the hymenophoral trama (lamellae or tubes) of 24 Basidiomycetes. These represent all the 16 Families of the Agaricales sensu Singer (1962). The typical members of the Agaricales in a limited definition have to be characterised by a more or less regular or bilateral trama with enlarged cells, or with swollen cellwalls in the Boletaceae, Strobilomycetaceae, Gomphidiaceae and Paxillaceae. In species of the genera Polyporus, Pleurotus (Polyporaceae), Lentinellus and Crepidotus such enlarged or swollen cells are lacking, the trama is irregular and is composed of a dense network of thickwalled hyphae. These genera and others like Schizophyllum better can be classified in the Aphyllophorales.