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Nitrogen isotopes reveal independent origins of N2-fixing symbiosis in extant cycad lineages
Michael A. Kipp, Eva E. Stüeken, Caroline A. E. Strömberg, William H. Brightly, Victoria M. Arbour, Boglárka Erdei, Robert S. Hill, Kirk R. Johnson, Jiří Kvaček, Jennifer C. McElwain, Ian M. Miller, Miriam Slodownik, Vivi Vajda, Roger Buick
Nature Ecology & Evolution