Iberis cepeaefolia Wulfen in Jacq. Miscell. II. p. 28. 1781
Austria: Carinthia, ad pedem montis "Königsberg" prope Raibl in valle Canalensi, Jabornegg (Fl. Aust.-Hung. 588), Topotype
Icacorea granatensis Rusby, Descriptions of Three Hundred New Species of South American Plants, pp. 78-80. 1920
Columbia: Santa Marta, H.H. Smith 432 (1898-1901), ? Isotype
Icacorea herbert-smithii Rusby, Descriptions of Three Hundred New Species of South American Plants, p. 80. 1920
Columbia: Santa Marta, H.H. Smith 859 (1898-1901), ? Isotype
Ilex anomala H. & A., Bot. Beech. Voy. 111. 1841
Hawaiian Islands: Kona, O. Degener 20244, 16 Aug. 1949, Topotype
Ilex canariensis Poir., Encyc. Suppl. 3: 67. 1813
Canary Islands: Tenerife, Ladera de Santa Ursula, E. Asplund 1112, 5 May 1933, Topotype
Ilex nipponica Makino, Bot. Mag. Tokyo 33. 1900
Japan: Hida Prov., T. Makino, 1925, ? Type - Publication not Available
Ilex pringlei Standley, Contrib. U.S. Nat. Herb. 23: 675. 1923
Mexico: Puebla, Honey Station, C.G. Pringle 10003, 25 Apr. 1904, Isotype
Ilex tonii Lundell, Wrightia 4: 135. 1970
Mexico: Chiapas, Amatenango del Valle, A.S. Ton 2169, 14 Mar. 1967, Isotype
Iliamna remota Greene, Leafl. Bot. Obs. 1: 206-207. 1906
U.S.A.: Illinois, Altorf Isl., Kankakee River, E.E. Sherff 5050, 28 July 1947, Topotype
Inula denticulatae Borbas, Oest. Bot. Zeischr, 38: 325. 1888
Hungary: inter Budapest et Rakos-Palota, Borbas (Fl. ex Austro- Hungarica 3802), Topotype
Inula subfloccosa Rech. f. Anz. Österr. Akad. Wiss., Math.-Nat. 93: 101, 1956
Greece: Euboea, K.H. Rechinger 19045, 23 June 1958, Topotype
Ionoxalis obliqua Rose, N. Amer. Fl. 25: 38. 1907
Mexico: Hidalgo, Honey Station, C.G. Pringle 8892, 30 Apr. 1904, Isotype
Ionoxalis vallicola Rose, N. Amer. Fl. 25: 39. 1907
Mexico: Federal District, valley of Mexico, C.G. Pringle 11326, 8 July 1902, Topotype
Iphiona maris-mortui Eig & Feinbr., Israel J. Bot. 15: 22. 1966
Palestine: Moav, estuary of Arnon River, A. Eig, 3.4.1925, Paratype
Ipomoea caudata Fernald, Proc. Amer. Acad. 36: 489. 1901
Mexico: Morelos, Sierra de Tepoxtlan, C.G. Pringle 13590, 5 Sept. 1905, Topotype
Ipomoea hilarifolia Rusby, Descriptions of Three Hundred New Species of South American Plants, pp. 103-104. 1920
Columbia: Santa Marta, H.H. Smith 2109 (1898-1901), ? Isotype
Ipomoea igualensis Weatherby, Proc. Amer. Acad. 45: 427. 1910
Mexico: Guerrero, Iguala canyon, C.G. Pringle 10054, 21 Sept. 1905, Isotype
Ipomoea lozani Painter, Coult. Bot. Gaz. 43: 411. 1907
Mexico: Queretaro, San Juan del Rio, C.G. Pringle 10029, 18 Aug. 1905, ? Isotype
Iresine pringlei Watson, Proc. Am. Acad. 25: 161. 1890
Mexico: Jalisco, Guadalajara, C.G. Pringle 11698, 17 Oct. 1903, Topotype
Iris thompsonii Foster, Rhod. 38: 199-200. 1936
U.S.A.: California, Del Norte Co., Douglas Park on Smith River, J.W. Thompson 12903, 24 June 1936, Topotype
Irmischia aristata Rusby, Descriptions of Three Hundred New Species of South American Plants, pp. 93-94. 1920
Columbia: Santa Marta, H.H. Smith 1901 (1898-1901), ? Isotype
Isachne chinensis Merrill, Phil. J. Sci. Bot. 12: 102. 1917
China: Kwangtung Province, Loh Fau Mountain (Lofaushan), E.D. Merrill 10982, 9-27 Aug. 1917, Topotype
Isoetes acadiensis Kott, Can. J. Bot. 59: 2592. 1981
Canada: Nova Scotia, Halifax Co., L.S. Kott 521, 18 Aug. 1977, Holotype
Isoetes appalachiana D.F. Brunton & D.M. Britton, Rhodora 99:129. 1997
U.S.A.: Pennsylvania, Blair Co., Tipton Reservoir, Brunton & McIntosh 12274, 6 Aug. 1995, Isotype
Isoetes boryana Durieu, Bull. Soc. Bot. Fr. 8: 164. 1861
France: Sanguinet (Landes), Etang de Cazau, E.J. Neyraut, 23 juillet 1900, Topotype
Isoetes echinospora Durieu var. boottii Engelm., A. Gray, Man. Bot. ed. 5. 676. 1867
U.S.A.: Massachusetts, Middlesex Co., Woburn, Horn Pond, W. Boott, 16 Sept. 1869, Topotype
Isoetes echinospora Durieu ssp. muricata (Durieu) Boivin var. savilei Boivin, Amer. Fern Jour. 51: 85. 1961
Canada: Quebec, Great Whale River, D.B.O. Savile 792, 8 Sept. 1949, Holotype
Isoetes echinospora Durieu var. robusta Engelm., Trans. St. Louis Acad. Sc. 4: 380. 1882
U.S.A.: Vermont, Lake Champlain, Isle La Motte, C.G. Pringle, 20 Sept. 1879, Isotype
Isoetes echinospora Durieu var. truncata A.A. Eaton, Fern Allies 223, 260. 1905
U.S.A.: Alaska, Kodiak, Coville & Kearney 2336, 20 July 1899, Topotype
Isoetes flaccida Shuttlew. var. chapmanii Engelm., Trans. St. Louis Acad. Sci. 4: 388. 1882
U.S.A.: Florida, Jackson Co., Marianna, R.K. Godfrey 61963, 19 May 1962, Topotype
Isoetes georgiana Leubke, Amer. Fern. J. 82: 24. 1992
U.S.A.: Georgia, ca 7 km west of Coverdale, Brunton & McIntosh 11550, 7 July 1993, Topotype
Isoetes howellii Engelm., Trans. Acad. Sci. St. Louis 5: 385. 1882
U.S.A.: Oregon, Wasco Co., The Dalles, J.W. Thompson 4872, 17 June 1928, Topotype
Isoetes hyemalis D.F. Brunton, Castanea 59: 12-21. 1994
U.S.A.: North Carolina, Harnett Co., 16 miles southwest of Lillington on southside of State Road 27 in Barbeque Creek, Pryer et al. 959, 26 Jan. 1992, Holotype
Isoetes lacustris L. var. paupercula Engelm., Trans. St. Louis Acad. Sc. 4: 377. 1882
U.S.A.: Colorado, Middle Park, Grand Lake, G. Engelmann, 5 Aug. 1881, Type Collection Material
Isoetes lithophila Pfeiffer, Ann. Missouri Bot. Gard. 9: 135. 1922
U.S.A.: Texas, Burnet Co., Edwards Plateau, 1.6 km west of Marble Falls, Brunton & McIntosh 11049, 19 Mar. 1992, Topotype
Isoetes ×marensis D.M. Britton & D.F. Brunton, Can. J. Bot. 73: 1345-1353. 1995
Canada: British Columbia, Shuswap Highlands, east shore of Mara Lake ca. 7 km south of Sicamous, D.F. Brunton & K.L. McIntosh 11301, 22 Aug. 1992, Isotype
Isoetes microvela D.F. Brunton, Rhodora 100: 270. 1998
U.S.A.: North Carolina, Onslow Co., Maysville, banks of White Oak River, Brunton & McIntosh 12179, 21 May 1995, Isotype
Isoetes muricata Durieu, Bull. Soc. Bot. France 11: 101. 1864
U.S.A.: Massachusetts, Middlesex Co., Woburn, Horn Pond, W. Boott, 16 Sept. 1869, Topotype
Isoetes ×pseudotruncata D.M. Britton & D.F. Brunton, Can. J. Bot. 74: 51-59. 1996
Canada: British Columbia, Vancouver Island, N side of abandoned bridge over Puntledge River at outlet of Comox Lake, Brunton & McIntosh 11251, 13 Aug. 1992, Isotype
Isomeris arborea Nutt. var. globosa Cov., Proc. Biol. Soc. Wash. 7: 73. 1892
U.S.A.: California, Kern Co., W of Caliente, E.C. Twisselmann 5137, 2 May 1959, Topotype
Isopyrum savilei Calder & Taylor
Canada: British Columbia, Queen Charlotte Islands, Anchorage, Athlow Bay, west coast of Graham Island, Calder & Savile 21464, 13 June 1957, Paratype; Graham Island, mountain at head of McClinton Bay, Masset Inlet, Calder et al. 21578, 18 June 1957, Paratype; Graham Island, east side of Shields Bay, Calder & Taylor 23294, Paratype; mountain directly north of Mt. Stapleton, Shields Bay, Rennell Sound, Calder & Taylor 23375, 9 Aug. 1957, Paratype; Moresby Island, below Mt. de la Touche, Fairfax Inlet, Tasu Sound, Calder & Taylor 23566, 16-17 Aug. 1957, Paratype; Moresly Island, mountain at west end of Mosquito Lake, Calder & Taylor 23721, 24 Aug. 1957, Paratype
Isopyrum savilei Calder & Taylor, Madrono 17: 70. 1963
Canada: British Columbia, Queen Charlotte Islands, Moresby Island, Calder et al. 23055, 29 July-2 Aug. 1957, Holotype
Iva nevadensis Jones, Am. Nat. 17: 973. 1883
U.S.A.: Nevada, Mineral Co., road to Hawthorne, A. Tiehm 8327, 11 Sept. 1983, Topotype
Iva oraria Barlett, Rhod. 8: 26. 1906
U.S.A.: Massachusetts, Banks of the Charles River, Boston, H.H. Bartlett (Pl. Ex. Gray 293), 18 Sept. 1905, ? Isotype
Ivesia jaegeri Mungz & Johnston, Bull. Torrey Bot. Cl. 56: 165. 1929
U.S.A.: Nevada, Clark Co., Charleston Mts., Charleston Park, I.W. & C.B. Clokey 5498 (Pl. ex. Gray 718), 30 July 1935, 14 July 1936, Topotype
Ivesia lycopodioides Gray, Proc. Am. Acad. 6: 530. 1865
U.S.A.: California, Mt. Dana, J. Clausen 776, 20 Aug. 1933, Topotype
Ixanthus viscosus Greisbach, Gen. et Sp. Gent. 129. 1839
Canary Islands: Nivaria, Valle Orotava, E.R. Sventenius 76, 11 June 1947, Topotype
Ixeris versicolor DC. var. chrysantha Freyn, Publication unknown
Europe: Dahuria, Nertschinsk, F. Karo, (Pl. Dahur, 251a) 1889, ? Type Collection Material