You are most likely to confuse this species with Conocephalum salebrosum, which was only separated from C. conicum relatively recently in 2004. The paper introducing C. salebrosum is available in the resources section below, along with a link to a page comparing the 2 species. Some of the photos in the gallery show the 2 side by side for comparison.
In general, a very shiny thallus is a good indication of C. conicum. Dull-looking Conocephalums with a clearly reticulate surface growing away from water are good candidates for C. salebrosum and – until you can recognise them by ‘jizz’ – should be taken home for checking.Read the Field Guide account