This contribution to the knowledge of the Aphyllophorales is dedicated to Dr. M. A. Donk as a tribute to his life-long endeavour to put the systematics and the taxonomy of this challenging order on a sound basis. A collection of South Asian specimens of Ganoderma and various other collections have been studied taxonomically as to spore, pore and anatomical cutis characters by using a technique devised by the author (Steyaert, 1946: 137; 1947: 47); it allows microtome sections of botanical material to be mounted immediately in Canada balsam. Three genera and 15 of the 39 species studied are described as new. All species are from Indonesia except when indicated otherwise; they are Humphreya, Haddowia, Magoderna, and Ganoderma kosteri (The Netherlands), G. vanheurnii, G. manoutchehrii (Iran), G. dejongii, G. donkii, G. puglisii (Italy), G. bruggemanii, G. trulla, G. trulliforme, G. lamaoense (Philippines), G. leytense (Philippines), G. ahmadii (West Pakistan), Humphreya endertii, Haddowia aëtii, Magoderna vansteenisii (Indonesia and Australia). Eight new combinations are proposed, viz. G. petchii (Lloyd), G. weberianum (Bres. & Henn.), Humphreya lloydii (Pat. & Har.), H. coffeatum (Berk.), Amauroderma preussii (P. Henn.) (syn. Ganoderma sikorae Bres., G. rubeolum Bres.) (predominantly African), Haddowia longipes (Lév.), Magoderna infundibuliforme (Wakef.), M. subresinosum (Murrill). The names of two important species, to wit G. pseudoferreum (Wakef.) Over. & Steinm. and G. rivulosum Pat. & Har. become synonyms of previously published names, whose correct combinations are G. philippii (Bres. & Henn.) Bres., and G. weberianum (Bres. & Henn.) Nov. comb., respectively. Ganoderma lucidum (Curt. ex Fr.) Karst. and G. resinaceum Boud. are redefined especially on spore characters previously unreported and which prove infallible in distinguishing the two species. Ganoderma chaffangeonii Pat., G. sessile Murrill, G. polychromum (Copel.) Murrill, G. praelongum Murrill, G. argillaceum Murrill, and G. subperforatum Atk. are placed in the synonymy of G. resinaceum on the basis of their spore features. The genus Amauroderma as currently understood is critically examined. Three new genera ( Humphreya, Haddowia, Magoderna) are set up for a mixture of Amauroderma and Ganoderma species. Additional details and distributional information are given for the previously published species that received new combinations (mentioned above) as well as for the following species: Ganoderma applanatum (Pers. ex S. F. Gray) Karst., G. tornatum (Pers.) Bres., G. brownii (Murrill) Gilbertson, G. adspersum (Schulzer) Donk, G. mirabile (Lloyd) Humphrey, G. philippii (Bres. & Henn.) Bres., G. williamsianum Murrill, G. tropicum (Jungh.) Bres., G. flexipes Pat., G. chalceum (Cooke) Stey., G. amboinense (Lam. ex Fr.) Pat., G. subtornatum Murrill, G. lucidum (Curt, ex Fr.) Karst., G. resinaceum Boud, G. colossus (Fr.) C. F. Baker, and Amauroderma rugosum (Bl. & Nees) Torrend.