habitat_substrate_fungus
fungi|fungus|lichen
The perithecium-like ascomata of this fungus grow on the bark and suberose outgrowths of twigs of the smallleaved elm (Ulmus minor). Cork formation is normal in this tree species, and it is not caused by the fungus. Since we were unable to observe algae in close association with fungal ®laments of Cresporhaphis ulmi, and this did not cause any visible injury to the tree, we regard the species as saprophytic. Interestingly, C. ulmi was absent from non-suberose, but smooth zones of the twigs and new shoots. During the examination of many elm trees while searching for C. ulmi, a similar ecology was observed for several other unidentified fungi. In fact, their abundance caused difficulties when trying to ascertain the conidiomata belonging to C. ulmi. These were scarce, while amongst the most confusing was a coelomycete with narrowly fusiform, slightly falcate conidia, of c. 5-7 x 1 µm, but produced in 1 to 3 loci per conidiogenous cell. Also the empty cavity of some old ascomata was ®lled by an opportunistic Fusarium-like fungus with colourless, falcate, 3-7 septate conidia, 35-55x3.5-4 µm, which could be mistaken for macroconidia of C. ulmi. In addition to these, other mitosporic fungi were observed, one of the most frequent being a dematiaceous hyphomycete. When growing on bark of the trunk, C. ulmi was associated with nitrophilous lichen communities dominated by Phaeophyscia orbicularis, Physcia adscendens and Xanthoria parietina.
Cresporhaphis ulmi
Leptosillia slaptonensis