Araucariomyces Aime & McTaggart, gen. nov.
MycoBank number: MB 836625; Index Fungorum number: IF 836625; Facesoffungi number: FoF;
Type species: Araucariomyces fragiformis (Ces.) McTaggart, R.G. Shivas & Aime, this paper.
Entomology: From the host family, Araucariaceae.
Diagnosis: Differs from all other rust genera in forming the gametothallus on species of Agathis (Araucariaceae).
Description: These species are described and illustrated in Peterson (1966). Spermogonia amphigenous, intra-epidermal becoming sub-epidermal as they break through host walls, convex hymenium; similar to Group 1 (type 1) but with scant periphyses not visible in all mounts, similar to Rogerpetersonia. Aecia peridiate, aecidium-type, deep-set within swollen host tissues. Sporothallus unknown. On leaves of Agathis (Araucariaceae). Two known species.
Notes: – Two rust fungi with cupulate aecia on Agathis spp., formerly placed in the form-genus Aecidium, belong here. Our analyses consistently place these in a lineage separate from all other sequenced Pucciniales (Fig. 1). Despite over a decade of sampling rust fungi from Australia and Southeast Asia on hosts codistributed with Agathis species, we have been unable to locate a telial state for these rusts. Peterson (1968) ruled out the possibility that Araucariomyces represents an endocyclic form, because aeciospores of Ar. balansae germinate to produce germ tubes rather than basidia. As is conjectured with Rogerpetersonia, the life cycle may not produce a sporothallus, and instead has adapted to systemically infect their hosts possibly including a cryptic sexual or parasexual cycle.
Species