2 FIELD MUSEUM OF NATURAL HISTORY BOTANY, VOL. IV. 



Wallroth's other four species have been accorded various inter- 

 pretations by different authors, only one species, X. pennsyhanicum, 

 having definitely survived the several reductions to synonomy. 1 This 

 species appears to be correctly described by Britton and Brown (Illustr. 

 Fl., Edit. II, 3: 346, fig. 4137. 1913) and still more recently by Shull 

 (Bot. Gaz. 59: 476, fig. 2. 1915). Robinson and Fernald (Gray's Man., 

 Edit. VII, 829. 1908) refer X. pennsyhanicum Wallr. doubtfully to 

 X. canadense Miller, a species advanced in the eighth edition of Miller's 

 Dictionary but equated in the ninth (posthumous) edition with X. 

 orientate L., and likewise equated recently by O. Hoffmann (Engl. and 

 Prantl Naturl. Pflanzenfamilien 4 V : 223. 1894), Britton and Brown 

 (loc. cit.), and others. Shull (loc. cit.) maintains the names X. pennsyl- 

 vanicum and X. canadense separately for United States material and 

 illustrates each. But by X. canadense he means the species figured by 

 Britton and Brown (loc. cit. fig. 4139) as X. americanum Walt., a plant 

 formerly confused with the European X. strumarium L. 2 To us, however, 

 it seems safer to retain the name X. americanum Walt, and to reject the 

 name X. canadense Miller, at least until a thorough and painstaking 

 revision of the entire genus shall have been made. 



In the Herbarium of Field Museum are a number of specimens 

 which are clearly conspecific and which we regard as X. americanum 

 Walt. As will be seen below, these represent a range extending from 

 Illinois to New York, south to Florida and west to Texas: 



Dr. Geo. Vasey, Chicago, 111. (Herb. Field Mus. catalogue no. 

 467371); Earl E. Sherff 1826, prairie, Chicago, 111., Aug. 30, 1912 (Herb. 

 Field Mus. cat. no. 435932); F. C. Gates 10024, Hancock County, 111., 

 Sept. 10, 1916 (Herb. Field Mus. cat. no. 472764); Harry N. Patterson, 

 vicinity of Oquawka, 111. (Herb. Field Mus. cat. nos. 209229 and 

 209230); Elihu Hall, fields, etc., Menard Co., 111. (Herb. Field Mus. 

 cat. no. 206218); idem, 111. (Herb. Field Mus. cat. no. 453866); A. B. 

 Burgess 365, pasture, Prairie Rhonde, Mich., Sept. 27, 1903 (Herb. 

 Field Mus. cat. no. 144710); Dr. Chas. F. Millspaugh, banks of the 

 Susquehanna River, Vestal, N. Y., Sept. 10, 1886 (Herb. Field Mus. cat. 

 no. 18744); Dr. J. T. Rothrock, streets, Philadelphia, Pa., Sept. 22, 1877 

 (Herb. Field Mus. cat. no. 320565); A. A. Heller, on Little Conestoga 

 near Stoneroad's Mill, Lancaster Co., Pa., Oct. 5, 1901 (Herb. Field 



1 It must be remarked, however, that Wallroth's treatment of the genus, regard- 

 less of its merit or demerit, appears to have received all too scanty a study. Gray 

 (loc. cit.) omits all mention of Wallroth's names and so appears to have overlooked 

 them entirely. 



1 In passing, we note Shull to say "it is now known that X. strumarium has never 

 been introduced into America." But in 1912, Fernald (Rhodora 14: 239.) reported 

 finding a single large plant of "true X. strumarium" growing at Revere, Massa- 

 chusetts. 



