Oligoporus

Possibly a species of Hydnellum at an early stage of development. If I'm right there would eventually be a stem and cap with teeth (rather than gills or pores) on the underside of the cap. Overall the shape of a mature specimen is often somewhat funnel-shaped. The odd species or two in the genus are noted for reddish droplets on the cap (at least in moist conditions). I have seen such a droplet covered specimen just once, in New Zealand, so you have me envious! It would be nice to have a herbarium specimen (in particular to confirm the genus and hopefully get a species of the genus recorded for the ACT), so I'll have to go wandering in Aranda Bushland.

This fungus has some similarities with the Northern Hemisphere species Oligoporus guttulatus (or Postia guttulata). I have collected the Aranda Bushland specimen for lodgement with the Australian National Herbarium and carried out a brief microscopic examination. Here are my notes: Approx. 50 mm long, 25 mm breadth. Pore surface whitish but as yet covering only a small area. Flesh pinkish-white to very pale yellow-brown with embedded glassy, yellow-brown globules. Texture corky to rubbery. Taste: mild. Monomitic with clamped, hyaline hyphae, 3.2-6.4 mu diam (with walls up to 1.6 mu thick); scattered dark, golden-brown hyphae present, 2.4-5.6 mu diam. Pileus with some tufts composed of bundles of small numbers of hyphae with obtuse to swollen apices. No cystidia. Basidia 4-spored. Spores hyaline, smooth, inamyloid, thin-walled, ellipsoid-cylindric, 6.4-8.0 x 2.8-3.2 mu.

In order to get photos of the microscopic details I took some tiny pieces of tissue from the already dried specimen and rehydrated them, either in a weak potassium hydroxide (KOH) solution (a standard rehydrating method) or in Melzer's reagent (essentially iodine). I also used a phloxine, a red stain. I gently pressed each sample between a microscope slide and a cover slip to spread it out and make it all thinner. Unlike a carefully cut cross-section it's messy but a quick way of getting some idea of the microscopic detail. The basic building blocks in fungi are filaments called hyphae. In the top left you see some of the brown hyphae (against a bed of tissue made up of densely packed colourless hyphae). In the bottom left you can, in places, see what looks like a thick red line, a white band on each side and then two thin lines. The white bands are the thick walls of the hyphae. Phloxine doesn't stain the walls but does stain the central protoplasm. At the lower right are a couple of basidia. Spores are produced at the tips of the prongs but these basidia have lost their spores. In some fungi there is just a simple cross-wall between two neighbouring hyphal cells. In others there is a cross wall as well as an arching structure called a clamp connection. For those fungi where microscopic examination is essential for an identification, identification keys often ask you if clamp connections are present.