ROSACEAE. Pyrus malus: Auckland, Whangarei, 50 m.

Hymenophore annual, byssoid-membranous, adherent, effused forming irregular linear areas 2-15 cm long; hymenial surface bright pink or salmon, fading, velutinate, at length deeply areolately creviced; margin thinning out, arachnoid, white, adherent. Context white, 250-500 µm thick, basal layer of repent hyphae, intermediate layer of intertwined hyphae somewhat corymbose beneath the hymenium; generative hyphae 5-10 µm diameter, becoming narrower from base to surface, walls 3 µm thick in basal hyphae, 0.5-1 µm thick in the upper part of the context and subhymenium, without clamp connections. Hymenial layer to 60 µm deep, a dense palisade of basidia, paraphyses, and paraphysate hyphae. Basidia subclavate, 24-10 x 6-9 µm, bearing 2-4 spores; sterigmata erect, slender, to 4 µm long. Paraphyses irregular in shape and size, clavate or subclavate, 20-40 x 5-7 µm. Paraphysate hyphae scanty or abundant, projecting to 30 µm, cylindrical, to 4 µm diameter, septate. Spores oval, obovate, or subglobose, sometimes flattened slightly on one side, apiculate, 9-12(-14) x 7-9 µm, walls smooth, hyaline, 0.5 µm thick. CONIDIAL STAGE. Sporodochia erumpent, to 0.5 mm across, aggregated into linear or orbicular stromata 1-25 mm long; surface porose-reticulate, orange-red. Spores catenate, arising from stout conidiophores, irregular in size and shape, oval, angular, trigonal, or subglobose, 14-20 x 11-15 µm, walls smooth, hyaline, 0.5 µm thick, contents granular, orange.

DISTRIBUTION: Ceylon, East and West Indies, India, North America, Samoa, New Zealand.

HABITAT: Parasitic on branches, twigs, and leaves.

Specimens from which the description was drawn were collected upon living apple twigs and branches, taken from a neglected orchard. The fungus forms cankers upon these, many small laterals being killed. Although a common parasite in tropical regions, where it has been recorded on citrus, cocoa, rubber, and tea, it has also been recorded as attacking fig and apple trees in Louisiana by Edgerton (1911) under the name of Corticium laetum, a species not present in North America, according to Rogers & Jackson (1943, p. 296). The fungus is unusual in possessing a conidial stage, described as Necator decretus by Massee. Rant (1912) showed by the aid of cultures that it was a stage in the cycle of the species. C. salmonicolor may be identified by the large-diameter basal hyphae with thick walls, absence of clamp connections, dense basidial layer, somewhat large clavate basidia with brief sterigmata, and large oval or subglobose spores. Basidia and paraphyses develop in corymbs, although this can be seen only in sections from developing margins. Although Dastur placed the species under Pellicularia, its only resemblance to members of that genus lies in the stout basal hyphae, development of context and hymenium being typically that of Corticium. Its relationship lies with C. fuciforme, which exhibits somewhat similar stout hyphae, the contents staining deeply with aniline blue.

TYPE LOCALITY: Ceylon.

Cunningham (1963) described the fungus from New Zealand. Although a common parasite in tropical regions, it has been collected only from apple trees in a neglected orchard in Whangarei, North Auckland, where it formed cankers killing small lateral branches. In Kerikeri, also in North Auckland, it was collected from a single pear tree in a home garden.