I have yet to find anything that suggests that there is a specific species of Lily that is to be used medicinally. I have read the section in Mathwe Woods book on Lilium Loniforium (his reference was Easter Lily page 341)

Are all lily’s created equal producing the same medicinal benefits? I have purple/pink growing in my yard and whitish yellow growing in my neighbors yard and would like to harvest the flowers before they die off.

Thanks.