 He identified one candidate in "Trillium erectum" ("Beth root" or "Wake-robin"), a sapogenin called diosgenin which had previously been found in Japanese yams ("Dioscorea tokoro").Marker showed that both sarsasapogenin and diosgenin could be converted into both progesterone and other steroid hormones.The quantities of diosgenin that could be extracted from "T. erectum" were still unsatisfactory, so Marker looked for richer sources.