The Ceratocystis species on conifers

Seven Ceratocystis species are recognized as having conifers as their prima ry hosts, and these species comprise a monophyletic group. Despite bring mo rphologically similar, these taxa are distinguished by intersterility and i sozyme electromorphs. The first described species in the group. Ceratocysti s coerulescens (Munch) Bakshi, is neotypified: it causes bluestain of Picea and Pinus in Europe and North America. A similar species, Ceratocystis pin icola sp.nov., also causes bluestain but has thus far been recorded only on Pinus in Britain. In contrast, Ceratocystis resinifera sp.nov. has been re corded from Picea on continental Europe and North America and invades wound s of living trees. Ceratocystis polonica (Siemaszko) C. Moreau is neotypifi ed and distinguished ecologically from Ceratocystis laricicola Redfern & Mi nter; both species occur across Eurasia and are associated with Ips bark be etles on Picea and Larix, respectively. A key is presented for these specie s as well as the recently recognized species from North America. Ceratocyst is rufipenni Wingfield, Harrington, & Solheim and Ceratocystis douglasii (D avidson) Wingfield & Harrington, which occur on Picea and Pseudotsuga, resp ectively.