Austroboletus occidentalis
Austroboletus occidentalis, commonly known as the ridge-stemmed bolete, is a species of bolete fungus found in Australia. It was described as new to science in 1986 by mycologists Roy Watling and Norma M. Gregory. The species name "occidentalis" is derived from the Latin "occidens" "west". The fruit body has a 5.5–10 cm diameter cap that has a texture reminiscent of suede or chamois and can be sticky/slimy when young. Initially orange- or pinkish-brown, it is subconical with a thickened margin, and flattens with age and fades an ochre colour. Like other boletes, it has tubes  under the cap instead of gills. These are white in young specimens maturing to pink. The cylindrical white stipe is 7–16 cm tall and 1.7–2.5 cm wide, marked with deep lacunae. The white flesh bruises yellowish and has a bitter taste. The edibility is unknown. The spore print is brown, the spores are cylindrical, 15–19 x 5–6.5 μm and covered entirely with warty lumps. "Austroboletus occidentalis" is a component of jarrah ("Eucalyptus marginata") forests in southwestern Western Australia. It has been found in coastal scrub in southeastern Tasmania. "Austroboletus occidentalis" establishes a new type of plant-fungus symbiosis (feremycorrhiza; FM ) with both woody plants (e.g. jarrah: "Eucalyptus marginata") and herbaceous plants (such as wheat, barley and canola), which has been described recently. The presence of "A. occidentalis" is associated with increased growth and nutrient uptake in jarrah seedlings, despite the fact that mycorrhizal structures were not recovered from the roots of the eucalypt (no root colonization). Chemical and genetic analysis of the soil and plants showed that fungal hyphae were nearby the roots and that plants had increased levels of nutrients including phosphorus, nitrogen, sulphur, magnesium, and several trace elements. Furthermore, the 33P uptake study revealed that fungal hyphae do  not transfer nutrient directly to plants. Mobilization and solubilization of nutrients from minerals and soil particles could be one of the underlying mechanisms as the concentration of carboxylates in the rhizosphere soil is higher in plants involved in this symbiosis. However, there might be other unknown mechanisms behind the remarkable improvements in plant growth and nutrition.