Digitalis thapsi many characteristics of "D. purpurea" after four to five generations of cultivation, and that the former became indistinguishable from the latter, a report that was considered "probably" trustworthy by Charles Darwin. "D. thapsi" and "D. purpurea" hybrids are generally fertile. "Digitalis thapsi" is widespread in Spain. A biennial evergreen plant, it flowers in late spring. A study of the fruiting activity in "D. thapsi" showed that production, size and number of seeds were interrelated. Analysis has shown that seed weight is not related to the length of the cotyledon, and that the length of the fifth leaf can serve as
Recreational drug use part of the milieu of drug taking. The reasons for drug use appear to have as much to do with needs for friendship, pleasure and status as they do with unhappiness or poverty. Becoming a drug taker, to many people, is a positive affirmation rather than a negative experience.” Anthropological research has suggested that humans "may have evolved to counter-exploit plant neurotoxins". The ability to use botanical chemicals to serve the function of endogenous neurotransmitters may have improved survival rates, conferring an evolutionary advantage. A typically restrictive prehistoric diet may have emphasised the apparent benefit of consuming psychoactive drugs, which