Type: Radicicolous Fungi; Description: Colonies on malt extract agar dark grey to olivaceous with dark concentric rings, no aerial mycelium. Conidiophores occurring singly or in groups of up to three, stipe erect, 200–500 µm long, olivaceous, simple, bearing 2–3 primary metulae 15–25 μm long; three to four additional series occur above the primary metulae, each giving rise to 2–4 further metulae at the apex; primary metulae light olivaceous, further metulae light olivaceous to hyaline. Conidiogenous cells discrete, tapering slightly, 15–20 μm long, hyaline. Conidia obovoid to broadly ellipsoid with truncate bases, 0-septate, 3–5 × 1–3 μm, smooth, hyaline, accumulating in a mucilaginous mass.

Distribution: Northland, Auckland, Coromandel, Waikato, Bay of Plenty, Taranaki, Taupo, Rangitikei, Wanganui, Wellington, Gisborne, Hawkes Bay, Wairarapa, Nelson, Westland, Marlborough Sounds, Marlborough, North Canterbury, Mid Canterbury, South Canterbury, Dunedin, Southland.; 1st Record: Shaw & Dick (1980: as Verticicladiella sp.).

Significance: Species of Leptographium have been associated with death of individual Pinus radiata and P. strobus trees in many parts of New Zealand (Shaw & Dick 1980; MacKenzie & Dick 1984). Infected trees show a black stain in the roots and in sapwood at the base of the tree. Resin bleeding at the base is common in P. radiata. Infected trees usually die quickly but some persist for up to 8 years with thin chlorotic crowns. Infection has been recorded only in forests on heavy clay soils prone to waterlogging. Many tree stands containing infected trees were grazed by cattle that damage surface roots and compact the soil. Stress caused by waterlogging and root disturbance appears to be main factor leading to death of infected trees. Species of Leptographium known to be present in New Zealand (L. alethinum, L. euphyes, L. lundbergii, and L. procerum) were found to be mildly pathogenic to P. radiata and P. strobus. Pinus strobus was more susceptible to infection than P. radiata and waterlogging made plants of both species more susceptible (M.A.Dick, unpublished data).; Host(s): Pinus radiata, P. strobus.

Multilocus phylogenetic analyses of 33 isolates revealed nine well-supported lineages in the L. procerum complex. Six of these lineages represented previously described species. These included L. procerum, for which an epitype is designated [Epitype (designated here): USA, Maine, Massabesic Experimental Forest, from Dendroctonus valens gallery on Pinus resinosa, Nov 2009, coll. M. J. Wingfield. PREM 61058 (herbarium specimen of dried culture); CMW 34542 = CBS 138288 (ex-epitype culture), MBT 198257.]