My research focuses on the taxonomy, systematics, speciation, biogeography and natural history of North and South American plants using macro and micro-morphology, and molecular systematics. Currently researched groups include the flowering plant families Gentianaceae (gentians; Macrocarpaea, Symbolanthus), Brassicaceae (Parrya), Bromeliaceae (Alcantarea, Vriesea, and Werauhia), Loganiaceae (Bonyunia), and the fern family Ophioglossaceae (Botrychium). Geographical regions where I largely conduct my research include the Andes in South America (Venezuela, Colombia, Ecuador, Peru, and Bolivia), and Arctic and mountainous regions of North America, Europe and Asia.

• Rapid allopolyploid radiation of moonwort ferns (Botrychium; Ophioglossaceae) revealed by PacBio sequencing of homologous and homeologous nuclear regions
  Dauphin, B; Grant, JR; Farrar, DR; Rothfels, CJ
  MOLECULAR PHYLOGENETICS AND EVOLUTION, 120 342-353; https://doi.org/10.1016/j.ympev.2017.11.025 MAR 2018
• L’herbier d’Abraham Gagnebin (1707-1800) du Musée d’histoire naturelle de La Chaux-de-Fonds.
  Chèvre M, Berret J, Goetschi F, Jacquat M, Grant JR. 2017.
  Bulletin de la Société neuchâteloise de Sciences naturelles 137 : 57-114.
• A Worldwide Molecular Phylogeny Provides New Insight on Cryptic Diversity Within the Moonworts (Botrychium s. s., Ophioglossaceae)
  Dauphin, B; Farrar, DR; Maccagni, A; Grant, JR
  SYSTEMATIC BOTANY, 42 (4): 10.1600/036364417X696483  2017
• Phylogeography of the moonwort fern Botrychium lunaria (Ophioglossaceae) based on chloroplast DNA in the Central-European Mountain System 
  Maccagni, Alessio; Parisod, Christian; Grant, Jason R. 
  ALPINE BOTANY, 127 (2): 185-196 10.1007/s00035-017-0188-8 2017
• A community-derived classification for extant lycophytes and ferns 
  Pteridophyte Phylogeny Grp. Schuettpelz, Eric; Schneider, Harald; Smith, Alan R.; et al. 
  JOURNAL OF SYSTEMATICS AND EVOLUTION, 54 (6): 563-603 https:doi.org/10.1111/jse.12229 2016
• Gentianaceae pp. 1344-1353 In: Catálogo de plantas y líquenes de Colombia. Volumen I. Capítulos introductorios – Líquenes a Lythraceae.
  Grant, JR, L. Struwe, J; Pringle, B; von Hagen, J; Molina & K. Lepis. In : Eds. R. Bernal, S.R. Gradstein, & M. Celis.
  Universidad Nacional de Colombia, Bogotá. (2016)
• Molecular phylogenetics supports widespread cryptic species in Mooworts (Botrychium ss, Ophioglossaceae) 
  Dauphin, Benjamin; Vieu, Julien; Grant, Jason R. 
  AMERICAN JOURNAL OF BOTANY, 101 (1): 128-140 10.3732/ajb.1300154 2014
• Taxonomy and lectotypification of Vriesea fenestralis Linden et Andre (Bromeliaceae) 
  de Moura, Ricardo Loyola; Grant, Jason R.; da Costa, Andrea Ferreira 
  JOURNAL OF THE TORREY BOTANICAL SOCIETY, 140 (3): 329-333 10.3159/TORREY-D-12-00082.1 2013

• Plant systematics
• Plant dispersal from Asia to North America
• Population genetics of Botrychium
• Patterns of speciation of plants in montane South America

• Floristics of Switzerland
• Herbarium studies