Asclepias quadrifolia (Four Leaved Milkweed)
Part of the Botany Libraries, Gray Herbarium Library, Harvard University Repository
The Harvard University Herbaria houses five research libraries that are managed collectively as the Botany Libraries. The Gray Herbarium Library specializes in the identification and classification of New World plants with emphasis on North American plants. The Archives of the Gray Herbarium houses unique resources including personal papers, institutional records, field notes and plant lists, expedition records, photographs, original artwork, and objects from faculty, curators, staff, and affiliates of the Gray Herbarium.
Harvard University Herbaria
22 Divinity Ave
Cambridge MA 02138 USA