Annulohypoxylon

The cobblestone-like growth in Photo 1 was growing on a well-rotted Hakea stump in a suburban garden. Within each 'cobblestone' is a roughly hemispherical chamber (or perithecium) in which sexual spores are produced. Sometimes the perithecia are damaged and towards the left hand edge of the photo you can see several damaged perithecia, their upper sections having been broken off and removed, leaving just the lower half of each perithecium as a remnant. The white scale bar in Photo 2 represents 5 millimetres. Also present on the wood was the somewhat powdery, khaki-coloured mass you see in Photo 3. In that khaki area numerous asexual spores have been produced and it is possible that this is the asexual (or anamorphic) state of this species. Identification of Annulohypo9xylon species relies on a mix of macroscopic and microscopic features and, for at least some species, a simple chemical test, the result of which is easy to see with the naked eye. In a weak aqueous potassium hydroxide (KOH) solution the species of Annulohypoxylon may exude olivaceous, purplish, orange or rusty pigments. To produce Photo 4 I placed one perithecium in a drop of KOH on a microscope slide and waited for a minute or two. The white square surrounds the perithecium and you see that from it an olivaceous pigment has diffused into the solution. The large fuzzy grey circle is the edge of the KOH drop. This material will be lodged as collection number HL 6143 at the Australian National Herbarium.