Asclepias tuberosa L.

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American medicinal plants New York,Boericke & Tafel,c1887. biodiversitylibrary.org/page/26078058

Flora conspicua London :Longman, Rees, Orme, Brown, and Green,1826. biodiversitylibrary.org/page/7372162

How to know the wild flowers :. New York :Scribner's,1893.. biodiversitylibrary.org/page/10769425