STUDIES ON ECTOMYCORRHIZAE .59. ECTOMYCOR RHIZAE OF TUBER-MELANOSPORUM, TUBER-MESENTERICUM AND TUBER-RUFUM (TUBERALES) ON CORYLUS-AVELLANA

The ectomycorrhizae of Tuber melanosporum, T. mesentericum and T. rufu m are comprehensively described and compared. Tuber melanosporum posse sses pseudoparenchymatous mantles with epidermoid cells; tree-like, ra mified cystidia furnished with a granular surface and ring-like thicke nings at their branching points originate from a hyphal net, which ove rlays the pseudoparenchymatic proper mantle; emanating hyphae were not found. Tuber mesentericum forms pseudoparenchymatous mantles with ang ular cells, cystidia - also with a granular surface - are at most once ramified at their base; they originate either directly from the mantl e cells or they are formed on short hyphal bridges between mantle cell s; emanating hyphae are infrequent. Tuber rufum produces a pseudoparen chymatous mantle with epidermoid cells; no cystidia are formed but ema nating hyphae occur frequently, and a hyphal net on the proper mantle is characteristic, too. The axes of the mycorrhizal systems of T. rufu m are, in contrast to those of T. melanosporum and T. mesentericum, co nsiderably thicker than their side branches; exclusively there, heaps of disrupted cells are formed.