(The specific epithet refers to Mahinapua Forest, the location of the holotype).

Sarcostroma mahinapuense has been consistently found on swollen, fissured cankers on branches of Eucalyptus nitens (14-19 years old) growing in Mahinapua Forest on the West Coast of the South Island. The cankers were first noticed in August 1998 and by June 1999 were to be found in about 60 ha of E. nitens. The number of cankers per affected tree had increased over this period and dieback, associated with cankers on smaller branches, was occurring. This fungus has also been recorded on E. regnans from Rotorua where it was associated with twig lesions and minor dieback. A further collection of the fungus was made in 1998 from the Nelson bioregion where it was associated with minor dieback ofEucalyptus sp. Sarcostroma mahinapuense appears to be acting as a pathogen on the West Coast. Its pathogenic status is being investigated.

The principal characters that separate S. mahinapuense from the other 5-septate Sarcostroma species are conidial length and the length:width ratio (Table 2).

S. mahinapuense spores 46 x 10 µm; L/W ratio 4.6:1; Apical appendage 15 µm; Basal appendage 12.5 µm
S. coryneoideum spores 34.5 x 10.2 µm; L/W ratio 3.4:1; Apical appendage 5.7 µm; Basal appendage 4.5 µm
S. foliicola spores 20.2 x 7.5 µm; L/W ratio 2.7:1; Basal appendage 6 µm; Apical appendage 6.5 µm
S. insidens spores 38 x 13 µm; L/W ratio 2.9:1; Apical appendage 17.3 µm; Basal appendage 17.8 µm
S. kennedyae spores 19 x 6.3 µm; L/W ratio 3:1; Apical appendage 15 µm; Basal appendage 13 µm
S. leucopogonis Spores 20.7 x 8 µm; L/W ratio 2.6:1; Apical appendage 2.2 µm; Basal appendage 3 µm
S. mariae Spores 25 x 5.7 µm; L/W ratio 4.4:1; Apical appendage 11 µm; Basal appendage 13.5 µm
S. plagiochaetum Spores 32 x 9 µm; L/W ratio 3.6:1; Apical appendage 10 µm; Basal appendage 7 µm
S. sinicum Spores 21.5 x 6.6 µm; L/W ratio 3.2:1; Apical appendage 6.5 µm; Basal appendage 7 µm

* Data for all species, except S. mahinapuense, are from Nag Raj (1993).