A revision of Verticillium section Prostrata. IV. The genera Lecanicilliumand Simplicillium gen. nov.

A major part of the species formerly classified in Verticillium sect. Prost rata is transferred to Lecanicillium. Fifteen species are named in Lecanici llium (of which three are new species), and two, of which insufficient mate rial is available, are informally treated. Taxa with conidial chains are no t included. Four taxa with mainly solitary phialides, which form a distinct clade outside that of Lecanicillium, are classified in the new genus Simpl icillium with the necessary new combinations. Simplicillium wallacei is int roduced as a new species close to S. lamellicola, together with its new tel eomorph, Torrubiella wallacei. Among numerous isolates originally identified as V lecanii, ten, mainly tro pical isolates are considered to represent this species, 24 belong to L. mu scarium, five to L. longisporum, and four to L. nodulosum I I isolates are reclassified as Simplicillium lanosoniveum. The concept of the former Verti cillium psalliotae is also restricted, for which nine isolates are represen tative. Chlamydospore-producing parasites of rust fungi identified under th is species or as Verticillium epiphytum are only distantly related to Lecan icillium and cannot yet be satisfactorily classified. Aphanocladium aranear um, with its rapidly collapsing aphanophialides, is closely related to L. p salliotae and is included in this genus as L. aphanocladii nom. nov. In con trast, the type species of Aphanocladium, A. album, is quite unrelated. Lec anicillium dimorphum, having both kinds of conidiogenesis, links L. psallio tae with L. aphanocladii. Engyodontium aranearum forms another member of th is complex. Because it is quite distinct from the type species of the genus , it is reclassified in Lecanicillium under the new name L. tenuipes. A sin gle isolate is available that matches L. aranearum, while the similar new s pecies L. evansii is be based on five isolates. Two other new species are L . attenuatum and L. acerosum. A neotype is designated for L. psalliotae, ep itypes are designated for L. muscarium, L. nodulosum, and L. aphanocladii.