Confirming the identity of a toxic exotic Lepiota.

Teresa Lebel (Botanic Gardens & State Herbarium of South Australia); Pamela Catcheside (Hon. Assoc., Botanic Gardens & State Herbarium of South Australia).

Identifying toxic mushrooms can be problematic as the remnants left after ingestion are often fragmentary and in poor condition. While microscopic examination can help narrow down possible genera, it is often difficult to determine species. Another issue is that many cases of ingestion occur in urbanised areas, which means the mycologist must consider the possibility of exotic as well as native fungi. DNA was extracted and the nuclear ITS and LSU sequenced from 9 symptomatic poisons case samples, ranging from 1961 to 2022. Five of the cases involved humans, and 4 dogs. One sample was confirmed as a species of Cortinarius, one a Psathyrella, and the remaining seven as the exotic toxic species, Lepiota brunneoincarnata. A fresh sample of tissue was tested with an AMATOXtest, designed to detect amatoxins, resulting in a positive reaction.