A. CAMPESTRIS. 125 



shows spicate clusters on the same plant with a paniculate one. A plant from the Gasp6 Peninsula (Fernald 

 and Collins 754) possesses one paniculate and two spicate stems, and Fernald states that the inflorescence 

 varies with the situation. In moist protected soils the plants are larger and the clusters paniculate, while in 

 drier or more exposed places they are reduced, and the inflorescence becomes spicate. In recent floras canaden- 

 sis is characterized with green involucres and borealis with brown, but these colors are not sharply defined in 

 the plants themselves. 



9. A. CAUDATA Michaux, Fl. Bor. Am. 2:129, 1803. — A. campestris caudata. 



10. A. CAUDATA CALVENS Lunell, Am. Midi. Nat. 2:188, 1912. — From the description this appears to be the 

 form of A. campestris caudata in which the herbage is thickly tomentulose when young. Type locality, in 

 gravel at Willow City, Bottineau County, North Dakota. 



11. A. COMMUTATA DOUGLASIANA Besser, Bull. Soc. Nat. Mosc. 8:70, 1835.— Referred in N. Am. Fl. to A. 

 camporum Rydberg, here considered a minor form of A. campestris pacifica. Type locality, Saskatchewan. 



12. A. COMMUTATA HOOKERIANA Besser, 1. c. 70, 1835. — Same as A. desertorum hookeriana, which see. 



13. A. COMMUTATA RiCHARDSONiANA Besser, 1. c. 74, 1835. — Based on A. desertorum richardsoniana, which see. 



14. A. DESERTORUM DOUGLASIANA Bcsser, in Hooker, Fl. Bor. Am. 1:325, 1833. — Referred in N. Am. Fl. to 

 A. camporum Rydberg, which is here considered as a minor form of A. campestris pacifica. Type locality 

 not stated. 



15. A. DESERTORUM HOOKERIANA Bcsscr, 1. c, 325, 1833. — Apparently includes two or more of the subspecies 

 of A. campestris. Distribution originally given as throughout Canada and to the Arctic Circle. 



16. A. DESERTORUM RicH.*.RDSONiANA Besser, 1. c, 325, 1833. — Referred in N. Am. Fl. to A. maccallae, 

 which is here considered as a minor form of A. campestris borealis, but since it was first described as having ashy- 

 sericeous involucres it is more likely the subspecies spithamaea. Original distribution given as throughout 

 Canada and thence to the Arctic Circle. 



17. A. DESERTORUM scouLERiANA Bcsscr, 1. c, 325, 1833. — One of the subspecies of A. campestris, probably 

 pacifica. Type locality. Fort Vancouver and Straits of de Fuca. 



18. A. FORWOODi Watson, Proc. Am. Acad. 25: 133, 1890. — A. campestris caudata, but a form with the leaves 

 mostly canescent with a short villous pubescence. Type locality. Black Hills of South Dakota. This is chiefly 

 a western variation, but ranges east at least to Point Edward on Lake Huron {Macoun 26S4S), while typical 

 caudata occurs as far west as Wyoming (according to Rydberg, N. Am. Fl.). 



19. A. FORWOODI var. calvens Lunell, Am. Midi. Nat. 5:68, 1917. — A. campestris caudata. (See note under 

 A. caudata calvens.) 



20. A. groenlandica Wormskiold, Fl. Dan. 27 : 10, 1818.-^4. campestris spithamaea. Type locality, Green- 

 land. 



21. A. LEWisi Torrey and Gray, Fl. N. Am. 2:417, 1843 (excluding synonymy). — A. campestris caudata, but 

 a form with heads in a large, open panicle. Type locality, Missouri. 



22. A. maccallae Rydberg, N. Am. Fl. 34:254, 1916. — A. campestris borealis. Separated because of the 

 short outer bracts, these about one-half as long as the inner. The rather numerous heads are soon ascending or 

 erect. Type locality, gravelly slopes of Tunnel Mountain, vicinity of Banff, Alberta. 



23. A. manca Rydberg, N. Am. Fl. 34:256, 1916. — A. campestris spithamaea. This is a dwarf, compact 

 form of the far north, differing only in the lower stature (5 to 7 cm.) and short leaves (1 to 2 cm.). Type local- 

 ity, Cold Bay, Alaska. 



24. A. PACHTSTACHTA De CandoUe, Prodr. 6:114, 1837. — A. campestris pycnocephala. Erroneously referred 

 by De Candolle to the section Abrotanum, although also properly placed, but with erroneous distribution, in 

 the section Dracunculus under the name A. pycnocephala. 



25. A. PACIFICA Nuttall, Trans. Am. Phil. Soc. II, 7:401, 1841.— A. campestris pacifica. 



26. A. peucedanifolia Jussieu; Besser, Bull. Nat. Soc. Mosc. 8:91, 1835. — A. campestris borealis. 



27. A. pycnocephala De Candolle, Prodr. 6:99, 1837. — A. campestris pycnocephala. 



28. A. PYCNOSTACHYA Nuttall, Trans. Am. Phil. Soc. 11,-7:401, 1841.— A. campestris pycnocephala. Obvi- 

 ously an error in name. 



29. A. RiPicoLA Rydberg, N. Am. Fl. 34:256, 1916.— A. campestris spithamaea. In the North American 

 Flora this is separated from spithamaea in the key by the narrowly linear instead of linear-oblanceolate segments 

 of the basal leaves, but these are slightly oblanceolate as stated in the description. Furthermore, specimens of 

 the type collection from Biggs, Oregon, are almost exactly matched by others from the high mountains of Colo- 

 rado (for example, Cameron Pass, July 31, 1896, Baker, and Eagle Mountain, August 12, 1913, Allen). It thus 

 seems that neither constant morphologic characters nor geographic distribution gives support to this form. 



30. A. SCOULERIANA Rydberg, Bull. Torr. Club 33: 157, 1906.— Based upon A. desertorum scouleriana Besser, 

 which see. 



31. A. SPITHAMAEA Pursh, Fl. Am. Sept. 522, 1814.— A. campestris spithamaea. 



32. A. VARIABILIS AMERICANA Besser, Bull. Soc. Nat. Mosc. 8:24, 1835.— A. campestris caudata but a form 

 with large panicles. 



33. OuGosPORUs PTCNOCEPHALUs Lessing, Linnaea 6:524, 1831. — A. campestris pycnocephalus. 



